Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24
The hexagon-shape graphene nanoflakes (GNFs) limited by zigzag edges only (with doubly and triply coordinated atoms) have unique increased reactivity. Despite the high systems symmetry (D6h) the Carbon atoms in GNFs occupy non-equivalent positions. Can such physical and chemical characteristics of G...
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| Date: | 2022 |
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| Language: | English |
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Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2022
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Surface| _version_ | 1869291912191541248 |
|---|---|
| author | Карпенко, О. С. Лобанов, В. В. Картель, М. Т. |
| author_facet | Карпенко, О. С. Лобанов, В. В. Картель, М. Т. |
| author_institution_txt_mv | [
{
"author": "О. С. Карпенко",
"institution": "Інститут хімії поверхні ім. О.О.Чуйка Національної академії наук України"
},
{
"author": "В. В. Лобанов",
"institution": "Інститут хімії поверхні ім. О.О.Чуйка Національної академії наук України"
},
{
"author": "М. Т. Картель",
"institution": "Інститут хімії поверхні ім. О.О.Чуйка Національної академії наук України"
}
] |
| author_sort | Карпенко, О. С. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2023-04-20T10:24:32Z |
| description | The hexagon-shape graphene nanoflakes (GNFs) limited by zigzag edges only (with doubly and triply coordinated atoms) have unique increased reactivity. Despite the high systems symmetry (D6h) the Carbon atoms in GNFs occupy non-equivalent positions. Can such physical and chemical characteristics of GNFs, which depend of the atom position in the cluster, definition? This characteristic together with the simplicity of its calculation makes it possible to predict the properties of nanoflakes obtained from GNFs by introducing single and multiatomic vacancies into them or by replacing Carbon atoms with electron withdrawing and electron donating atoms. This characteristic includes the C1s core-level binding energy shifts, the maxima of which characterize the C atoms of a certain type.
The proposed work is devoted to quantum chemical calculations of the electronic density of states (DOS) of pristine hexagon-shape GNF C96 (multiplicity, M=5), their saturated counterpart –polycyclic aromatic hydrocarbon(PAH) C96H24 (M=1) and their derivatives with one and two single vacancies in the ground electronic state (GES). All calculations were performed using the density functional theory (DFT) method with the involvement of the valence-split basis set 6-31G (d,p). Systems with open shells were considered using the UB3LYP exchange-correlation functional. The obtained spectra were fitted using Gaussian curve fitting program to determine the binding energy for each peak.
The Gaussian function distribution of the theoretically calculated C1s core-level binding energy shifts of GNFs testified the presence of six peaks, each of which refers to a certain type of Carbon atoms. The C1s peak with the highest binding energy (-285.57 eV) is caused by contributions from the doubly coordinated edge cyclic chain (ECC) Carbon atoms. The C1s orbitals of the central hexagon (CHex) atoms and the first cyclic chain (FCC) atoms form delocalized molecular orbitals (MOs) in different parts of the cluster.
The analogous spectrum of PAH C96H24 is slightly shifted to the region of lower binding energies  and  contains  only  two well-defined  peaks.  The peak  with  a higher binding energy (-284.36 eV) is generated by the 1s states of the CHex atoms and the atoms of the FCC, which are bounded to the CHex atoms.
The electronic DOS difference in C1s core-level spectra of GNF C96 (M=5) and their saturated counterpart PAH C96H24 is established due to the presence of two weakly bounded π-systems in GNF and common conjugated system in PAH.
The electronic DOS of defect-containing cluster C96-1(1) (M=3) (one CHex atom has been removed from the C96nanoflake) is generated by the C1s core-level atoms of the second cyclic chain (SCC), which are located at the different distances from the center of the nanoflake. The peak of the lowest intensity (-284.63 eV) appears in the spectrum as a reflection of the appearance  of  doubly  coordinated  Carbon  atoms  surrounding  the  single  vacancy in the C96-1(1) nanoflake.
The analysis of the electronic DOS of the C1s core-level spectrum of the C96-2(1) nanoflakeis shown, that doubly coordinated Carbon atoms, concentrated around two single vacancies, are essentially non-equivalent. If the MO with the lowest binding energy is localized on two of them – the MO with the highest binding energy is localized on the third atoms (one around each single vacancy).
The electronic C1s core-level DOS spectrum of defect-containing molecular systems with one C96-1(1)H24 and two C96‑2(1)H24 single vacancies are similar to the analogous spectrum of PAH C96H24. In the first of them – one additional maximum appears due to C1s atoms surrounding the single vacancy. In the second – there are two additional maxima, each of which is generated by C1s core-level atoms adjacent to individual vacancies. |
| doi_str_mv | 10.15407/Surface.2022.14.063 |
| first_indexed | 2025-09-24T17:25:28Z |
| format | Article |
| fulltext |
Поверхня. 2022. Вип. 14(29). С. 63–77 63
UDC 544.18:546.26-162:544.723:544.43 doi: 10.15407/Surface.2022.14.063
C1s CORE-LEVEL BINDING ENERGY SHIFT DEPENDENCE
FROM CARBON ATOMS POSITION IN
GRAPHENENANOFLAKES C96 AND POLYCYCLIC
AROMATIC HYDROCARBON C96H24: A DFT STUDY
O.S. Karpenko, V.V. Lobanov, M.T. Kartel
Chuiko Institute of Surface Chemistry of the NAS of Ukraine,
17 General Naumov Str., Kyiv 03164, Ukraine. E-mail: karpenkooksana@ukr.net
The hexagon-shape graphene nanoflakes (GNFs) limited by zigzag edges only (with doubly
and triply coordinated atoms) have unique increased reactivity. Despite the high systems symmetry
(D6h) the Carbon atoms in GNFs occupy non-equivalent positions. Can such physical and chemical
characteristics of GNFs, which depend of the atom position in the cluster, definition? This
characteristic together with the simplicity of its calculation makes it possible to predict the
properties of nanoflakes obtained from GNFs by introducing single and multiatomic vacancies
into them or by replacing Carbon atoms with electron withdrawing and electron donating atoms.
This characteristic includes the C1s core-level binding energy shifts, the maxima of which
characterize the C atoms of a certain type.
The proposed work is devoted to quantum chemical calculations of the electronic density
of states (DOS) of pristine hexagon-shape GNF C96 (multiplicity, M=5), their saturated
counterpart –polycyclic aromatic hydrocarbon(PAH) C96H24 (M=1) and their derivatives with one
and two single vacancies in the ground electronic state (GES). All calculations were performed
using the density functional theory (DFT) method with the involvement of the valence-split basis
set 6-31G (d,p). Systems with open shells were considered using the UB3LYP exchange-
correlation functional. The obtained spectra were fitted using Gaussian curve fitting program to
determine the binding energy for each peak.
The Gaussian function distribution of the theoretically calculated C1s core-level binding
energy shifts of GNFs testified the presence of six peaks, each of which refers to a certain type of
Carbon atoms. The C1s peak with the highest binding energy (-285.57 eV) is caused by
contributions from the doubly coordinated edge cyclic chain (ECC) Carbon atoms. The C1s
orbitals of the central hexagon (CHex) atoms and the first cyclic chain (FCC) atoms form
delocalized molecular orbitals (MOs) in different parts of the cluster.
The analogous spectrum of PAH C96H24 is slightly shifted to the region of lower binding
energies and contains only two well-defined peaks. The peak with a higher binding energy (-
284.36 eV) is generated by the 1s states of the CHex atoms and the atoms of the FCC, which are
bounded to the CHex atoms.
The electronic DOS difference in C1s core-level spectra of GNF C96 (M=5) and their
saturated counterpart PAH C96H24 is established due to the presence of two weakly bounded π-
systems in GNF and common conjugated system in PAH.
The electronic DOS of defect-containing cluster C96-1(1) (M=3) (one CHex atom has been
removed from the C96nanoflake) is generated by the C1s core-level atoms of the second cyclic
chain (SCC), which are located at the different distances from the center of the nanoflake. The
peak of the lowest intensity (-284.63 eV) appears in the spectrum as a reflection of the appearance
of doubly coordinated Carbon atoms surrounding the single vacancy in the C96-1(1) nanoflake.
The analysis of the electronic DOS of the C1s core-level spectrum of the C96-2(1) nanoflakeis
shown, that doubly coordinated Carbon atoms, concentrated around two single vacancies, are
64
essentially non-equivalent. If the MO with the lowest binding energy is localized on two of them –
the MO with the highest binding energy is localized on the third atoms (one around each single
vacancy).
The electronic C1s core-level DOS spectrum of defect-containing molecular systems with
one C96-1(1)H24 and two C96-2(1)H24 single vacancies are similar to the analogous spectrum of PAH
C96H24. In the first of them – one additional maximum appears due to C1s atoms surrounding the
single vacancy. In the second – there are two additional maxima, each of which is generated by
C1s core-level atoms adjacent to individual vacancies.
Keywords: hexagon-shape graphene nanoflake(GNF), polycyclic aromatic hydrocarbon (PAH),
electronic density of states (DOS), C1s core-level shift, density functional theory (DFT), defect-
containing nanoflake, single vacancy, Gaussian curve fitting.
Introduction
Graphene is a two-dimensional (2D) structure composed of Carbon (C) atoms located in
the nodes of a crystal lattice of the honeycomb type and connected to each other exclusively by
covalent bonds.
Graphene itself, as an infinite two-dimensional system of carbon atoms, is a chemically
inert substance that is not very suitable for the needs of microelectronics, due to the zero density
of one-electron states at the Fermi level and the absence of a band gap. It is possible to get rid of
these shortcomings in several ways, namely: making the graphene-like systems of finite size, i.e.
limiting the graphene sheet with edges of a certain type; creating adjustable sets of single and
multiatomic vacancies, or holes (defects) of a certain size in the graphene lattice; substituting the
C atoms in the graphene lattice by electron withdrawing or electron donating hetero-atoms;
violating the periodic structure; atoms and molecules adsorption on the graphene plane.
The information of the link between the C atoms position in the graphene sample and its
physical and chemical properties is important when each of the listed methods or a sequence of
several of them is applying. The finite graphene-like samples with zigzag edges are the most
interested due to theirs increased reactivity of doubly coordinated C atoms. The creation of
different types of vacancies lead to an increase the number of C atoms types.
The existence of two weakly interconnected conjugated systems in hexagon-shape
graphene nanoflakes (GNFs), and a single π-system – in polycyclic aromatic hydrocarbon (PAH)
with similar structure, was established in our previous works [1 – 4] using quantum chemistry
study. To confirm the existence of different types of Carbon atoms in GNF compared to PAH, was
decided to calculate the electronic density of states (DOS) and study the C1s core-level binding
energy shifts of both structures. In the future, it is possible to predict the structure of systems with
optimal reactivity to facilitate their experimental studies based on the obtained theoretical data.
All calculations were performed using the software module US GAMESS [5] by the
density functional theory (DFT) method [6, 7] with exchange-correlation functional by the B3LYP
[8, 9] in the 6-31 G(d,p) basis set.
The C1s core-level binding energy peaks of GNF96
In [1] was shown – the size of hexagon-shape GNFs C96 with zigzag edges is enough to
pass the properties of the larger size structures. The fig. 1 shows the curve of atomization energy
(Eat
#, kJ/mol) depend from the number of Carbon atoms in hexagon-shape GNFs C6 – C294. The
atomization energy was calculated for the ground electronic state(GES) and refers to one C-C
bond. The Eat
# decreases exponentially for first three GNFs (С6–С54) and then it linearly depends
on the cluster size starting from C96 nanoflake. The line moving to the nanoflake C216 reaches a
plateau. The analysis of the results of the calculation properties of GNFs C6–C294 testified to their
similarity and weak dependence on the number of Carbon atoms in the nanoflake. Therefore, in
65
the future (as typical illustrations), the data obtained for GNF C96in the quintet GES (M=5) and
their saturated counterpart PAH C96H24 (M=1) in the singlet GES will be considered in detail.
Fig. 1. Atomization energy averages over
all the Carbon-Carbon bonds in
GNFs C6–C294 as a function of the
cluster size
As known from literature [9, 10], devoted to electronic DOS calculations, the core-level
binding energy shifts depend on their chemical environment in molecular system. To comparing
the theoretically obtained values with experimentally measured values, the correction coefficients
were introduced to compensate the quantum chemical methods errors for various types of atoms
and atomic orbitals.
To reproduce the electronic DOS of GNF C96 (M=5) in the C1s core-level binding energy
range, the correction coefficients of the energy scale 1.024 was used. Its value was found as the
ratio of the value of 284.3 eV obtained in the experiment [9] (characteristic of the 1s core level of
the sp2-hybridized C atom) to 277.6 eV, which is given by the calculation of this binding energy
level of the C atom in the approximation used in the work (TFG, B3LYP, 6-31G (d, p)). The same
value 1.022was given in [10].
In GNFC96 atoms occupy several non-equivalent positions. For example, fig. 2 (which
shows the atoms numbering in GNF C96nanoflake) shows the edge cyclic chain (ECC) contains of
three types Carbon atoms: doubly and triply coordinated and those that participate in the formation
of almost triple C≡C bonds at the junctions of zigzag edges.
The non-equivalence of the Carbon atoms in the GNF is determined by the degree of
hybridization of the atomic orbitals (AO), the chemical environment (the number of neighboring
Carbon atoms), and possibly, their distance from the nanoflake center. The ten types of C atoms
were determined in GNF C96 (M=5) depending on the specified factors. So there are 6 atoms of
type «2», type «4» – 6, type «14» – 12, type «18» – 12, type «34» – 12, type «6» – 6, type «8» –
6, type «50» – 12, type «22» – 12 and type «38» – 12 atoms. For the C96 nanoflake (fig. 3), which
in the experiment is identified with the photoelectron spectrum, the number of certain atoms type
determines the intensity of lines in the theoretically calculated DOS spectrum in the C1s core-level
binding energy range.
When Carbon atom is a part of a molecule or GNF, the binding energy of its 1scoreorbital
undergoes a certain shift depending on the chemical environment of the C atom. At the same time,
the C1s AO, in many cases, is almost 100% localized on one of the atoms, which leads to the fact
that some of the lowest-energy molecular orbitals (MOs) of the nanoflake consist exclusively of
the C1s orbital of one or another atom. So, for example, the α-MO GNF C96 (M=5) number one is
with the lowest energy -285.86 eV (in the binding energy range with correction coefficients), the
contribution of C1s AO with number 38 is 98% (fig. 4).
66
Fig. 2. Structure of GNF C96 nanoflake with
number of main type of atoms and
designation of the cyclic chains of
Carbon atoms: CHex – Central
Hexagon, FCC – First Cyclic Chain,
SCC – Second Cyclic Chain, ECC –
Edge Cyclic Chain
Fig. 3. C1s core-level DOS spectrum of GNF
C96 (M=5) and its fitting by Gaussian
functions
Fig. 4. Spatial localization of number one MO
GNF C96 (M=5) in GES, which is on
98 % represented by C1s orbital with
number 38 (numbering of atoms is
shown in fig. 2)
Applying the above-described procedure for determining the energy of MOs localized on
certain atoms of GNF C96 (М=5), the peak assignment of the theoretically calculated electronic
DOS spectrum in the C1s core-level binding energy range was performed. Thus, the peak with an
energy of -285.86 eV refers to C1s core-level (fig. 4) of type 38 atoms, i.e., triply coordinated C
atoms of the ECC. There are 12 atoms of this type in total. The peak with a binding energy of -
285.57 eV is caused by contributions from C1s core-level state of doubly coordinated Carbon
atoms (type 22), their number is also 12. The maximum in the electronic DOS spectrum with a
binding energy of -285.38 eV is formed by contributions from the local C1s electronic DOS of 12
67
carbon atoms of type 34 (binding energy -285.42 eV) and contributions from of the local C1s
electronic DOS of 12 atoms of type 18 with an energy of -285.38 eV. The three maxima in the
core-level electronic DOS spectrum of GNF C96 (M=5) with the lowest binding energies of -
285.14, -284.83, and -284.77 eV are due to the C1s-electron states of types 6, 8, and 50,
respectively.
Analysis of MO structure and binding energies showed that C1s AO of types 2, 4, and 14 form
MOs that are delocalized within one or another area of the С96nanoflake. In such cases, it makes no sense
to assert the possibility of attributing each peaks in the electronic DOS spectrum to a specific type or types
of atoms. The structure of one such nodeless delocalized MO is shown in fig. 5.
Fig. 5. Structure of the lowest-energy
delocalized MO composed of AO
C1s GNF C96 (M=5)
The obtained data of the C1s electronic DOS spectrum of C96 GNF (M=5) have an
independent value for establishing the link between the position of the C atoms in the C96 nanoflake
and the position of C1s binding energy peak. The data will be used in considering the chemical
shifts in GNF with different types of vacancies in the future.
The C1s core-level binding energy peaks of PAH C96 H24
The C1s core-level binding energy peaks of PAH C96H24 (Fig. 6) is somewhat shifted to
the region of lower binding energies and is much simpler in comparison with the similar spectrum
of GNF C96 (M=5). It contains two well-defined peaks (-284.36 and -284.07 eV).
Fig. 6. DOS spectrum of PAH С96Н24 in the
C1s core-level binding energy range
and its fitting by Gaussian functions
In contrast to the case of GNF C96 (M=5), for PAH C96H24 no MOs composed of C1s core-
level states were detected and localized on one specific atom. As an example, in fig. 7 shows the
structure of the lowest-energy MO composed of AO С1s, which is delocalized on a group of 12
Carbon atoms in the central part of PAH. This MO, together with MOs localized on other groups
68
of atoms of the central part of PAH С96Н24, determine the peak with a binding energy of -284.36
eV in the 1s DOS spectrum. MOs distributed over the C atoms of ECC of PAH С96Н24 are
responsible for the peak with a binding energy of -284.07 eV (fig. 8). The difference between the
1s core-level electronic DOS spectra for GNF C96 (M=5) and PAH C96H24 is obviously caused by
the presence of two weakly bounded π-systems in the first of them and one conjugated system in
PAH.
Fig. 7. Structure of the lowest-energy MO
composed of С1s AOPAH С96Н24, the
electron binding energy of which
corresponds to the peak at -284.36 eV
in the 1s DOS spectrum
Fig. 8. Structure of one of the MOs composed
of С1s AO PAH С96Н24, the electron
binding energy of which corresponds
to the peak at -284.07 eV in the 1s
DOS spectrum
The position of Carbon atoms within the nanoflake C96, based on the theoretically
calculated energies of C1s core-level spectrum, can be determined only for Carbon atoms of the
ECC and SCC (see fig. 2). The localization of atoms within the FCC and the CHex cannot be
established, since their 1sorbitals are not localized on atoms, but form delocalized MOs.
For the PAH C96H24 the C1s core-level DOS spectrum can distinguish only the Carbon
atoms located on the periphery of the molecule from the atoms of the inner part of the molecule.
The C1s core-level binding energy peaks of defect-containing GNFs
The C1s core-level DOS spectrum of the defect-containing nanoflake C96-1(1) (M=3) (one
CHex atom has been removed from the C96 nanoflake) is similar to the C1s core-level DOS
spectrum of the defect-free nanoflake C96 (M=5) (fig. 6 and 9). As in the case of C96 (M=5)
considered above, the peak with the highest binding energy of 1s-electron (-286.32 eV) refers to
the most deeply placed MOs localized on the triply coordinated Carbon atoms of the ECC.
69
Fig. 9. C1s core-level DOS spectrum of
nanoflake C96-1(1) (М=3)and its fitting
by Gaussian functions
The next in binding energy (two closely spaced peaks with energies of -285.96
and -285.86 eV) are due to contributions from the C1s states of doubly coordinated Carbon atoms
of ECC, which are in non-equivalent positions. The peak of the highest intensity (-285.57 eV) is
generated by the C1s core-level atoms of the SCC, which are located at different distances from
the center of the nanoflake. As an example, we gives atoms of types 18 and 34 (fig. 9). The peaks
with lower binding energies (-285.38, -285.17 and -284.82 eV) are formed by contributions from
the C1s core-level atoms of types 6 (SCC), 8 (triply coordinated ECC atoms located in the central
part of each border) and 50 (double-coordinated Carbon atoms that take part in the formation of
almost triple bonds). Finally, the peak with the lowest intensity (-284.63 eV) appears in the
spectrum as a reflection of the appearance of doubly-coordinated Carbon atoms in the C96-1(1)
nanoflake, which surround the single vacancy (fig. 9). This can be considered evidence that the
properties of doubly coordinated Carbon atoms adjacent to the single vacancy differ from the
properties of similar atoms of ECC. Fig. 10 shows one of the three MO localized on one of the
atoms around the single vacancy. Each of the three Carbon atoms surrounding the single vacancy
has a concentrated MO similar in energy and structure.
The C1s core-level DOS spectrum of nanoflake C96-2(1) (two symmetrically placed Carbon
atoms of the SCC have been removed from nanoflake C96) in the energy range of the C1s core-
level (fig. 11) is somewhat more complex than the spectrum of nanoflake C96-1(1) with single
vacancy. This is reflected both in a greater number of intensity maxima and in a significant overlap
of the Gaussian functions, on which the spectrum was fitted. If for nanoflake C96-1(1) three
degenerate MOs are localized on all three doubly coordinated Carbon atoms surrounding the
vacancy, then for nanoflake C96-2(1) the situation is somewhat different. In particular, the MO with
the lowest energy is localized on Carbon atoms concentrated around two single vacancies (fig. 12),
and they correspond to the peak with a binding energy of -286.36 eV.
Fig. 10. Spatial localization of MO on one
of the doubly coordinated Carbon
atoms surrounding the single
vacancy in nanoflake C96-1(1).
70
Fig. 11. C1s core-level DOS spectrum of
nanoflake C96-2(1) (M=3) and its
fitting by Gaussian functions
Fig. 12. Spatial localization of MO on two
doubly coordinated carbon atoms
surrounding single vacancies in
nanoflake C96-2(1)
In contrast to the case of nanoflake C96-1(1), two closely spaced peaks (-285.94
and -285.83 eV) in the C1s DOS spectrum of nanoflake C96-2(1)are caused by triply coordinated
atoms of the twelve-member ring of each of the single vacancies (fig. 13).
Fig. 13. The spatial localization of MO on two
triply coordinated carbon atoms
surrounding single vacancies in
nanoflake C96-2(1).
The two peaks with the highest intensity (-285.66 and -285.51 eV) in the DOS spectrum of
C96-2(1) nanoflake are caused by contributions from C1s of the three-fold coordinated Carbon atoms
of the SCC, which is not disrupted during the formation of two single vacancies. Regarding the
peaks with energies of -285.27, -285.15 and -284.83 eV, no definite conclusions can be made due
to the presence of vacancies in the FCC of Carbon atoms. The peak with an energy of -284.49 eV
is due to the MO concentrated on the two Carbon atoms of the CHex, which surround the single
vacancy (fig. 14).
71
Fig. 14. Spatial localization of MO on doubly
coordinated carbon atoms of the
central hexagon surrounding single
vacancies in nanoflake C96-2(1)
Thus, from the analysis of the C1s DOS spectrum of nanoflake C96-2(1) it is clear that the
doubly coordinated Carbon atoms, concentrated around two single vacancies, are essentially non-
equivalent. If on two of them (one around each single vacancy) the MO with the lowest binding
energy is localized, then on the third atoms (one around each single vacancy) – with the highest.
The C1s core-level binding energy peaks of defect-containing PAHs
It was shown above, the moving from the C96 nanoflake(M=5) to the PAH C96H24 the C1s
core-level DOS spectrum is significantly simplified. A similar situation occurs when comparing
the spectra of the C96-1(1) and C96-2(1) nanoflakes on the one hand and – the spectra of the C96-1(1)H24
and C96-2(1)H24 systems on the another. Fig. 15 shows the C1s core-level DOS spectrum of PAH
C96-1(1)H24 (M=3). It contains two well-defined peaks of high intensity with binding energies
of -284.34 and -284.09 eV and a peak of much lower intensity corresponding to an energy
of -284.70 eV. This peak is generated by the C1s states of unsaturated atoms surrounding the single
vacancy (fig. 16).
The structure of MO, the energy of which corresponds to the peak of maximum
intensity -284.34 eV (fig. 17), is similar to the structure of MO PAH C96H24 (fig. 7), that is, this
peak is generated by the C1s atoms of the central part of the systemC96-1(1)H24 (M=3). The lower
intensity peak with the energy of -284.09 eV is caused by the Carbon atoms of the peripheral part
of the mentioned system. The spatial distribution of one of these MOs is shown in figure 18.
Fig. 15.C1s DOS spectrum of PAM
C96-1(1)H24(M=3) and its fitting by
Gaussian functions
72
Fig. 16. Spatial localization of MO on
doubly coordinated Carbon atoms
surrounding a single vacancy in the
C96-1(1)H24 system
Fig. 17. Spatial localization of MOs whose
energy corresponds to the
maximum intensity peak of -284.34
eV in the C1s core-level DOS
spectrum of PAH C96-1(1)H24 (M=3)
The DOS spectrum of PAM C96-2(1)H24(M=5) in the C1s core-level binding energy range
and its fitting by Gaussian functions are shown in figure 19. It differs from the similar spectrum
of C96-1(1)H24(M=3) system by the presence of one additional peak of low intensity with a binding
energy of -284.78 eV. This peak refers to the C1s states of unsaturated C atoms that surround each
of the single vacancies (fig. 20).
Fig. 18. Spatial localization of MOs whose
energy corresponds to the peak
at -284.34 eV in the C1s core-level
DOS spectrum of the C96-1(1)H24
system (M=3)
73
Fig. 19. Spectrum of the density of one-
electron states of PAM C96-2(1)H24
(М=5) in the energy interval of the
C1s core level and its
decomposition by Gaussian
functions
Fig. 20. Spatial localization of one of the MOs
on doubly coordinated carbon atoms
surrounding two single vacancies in
the C96-2(1)H24 system.
The peak with a slightly lower binding energy (-284.58 eV) is generated by C1s states of
triply coordinated Carbon atoms (fig. 21), which are located in twelve-member rings formed when
two C atoms are removed from PAH C96. Peaks with energies of -284.42 and -284.13 eV
correspond to the MO, composed of C1s states of C atoms that do not border by vacancies (fig.
22), and located on the periphery of the C96-2(1)H24 system(М=5) (fig. 23).
Fig. 21. Spatial localization of MOs whose
energy corresponds to the peak
at -284.58 eV in the spectrum of the
density of one-electron states of the
C96-2(1)H24system (М=5)
74
Fig. 22. Spatial localization of MOs, the
energy of which corresponds to the
peak of maximum intensity
of -284.42 eV in the spectrum of the
density of one-electron states of the
C96-2(1)H24 system (М=5)
Fig. 23. Spatial localization of MOs whose
energy corresponds to the peak
at -284.13 eV in the spectrum of the
density of one-electron states of the
C96-2(1)H24 system (М=5)
Conclusions
The lowest-energy C1s core-level of GNF C96 (M=5) is localized on ECC atoms, excluding
Carbon atoms, which take part in the formation of almost triple bonds at the junctions of zigzag
edges. The position of Carbon atoms within the nanoflake C96, based on the theoretically calculated
C1s DOS spectrum, can be determined only for the Carbon atoms of the edge cyclic chains and
second cyclic chains. The localization of atoms within the first cyclic chain and the central hexagon
cannot be established, since their 1sorbitals are not localized on atoms, but form delocalized
molecular orbitals.
For the polyaromatic molecule C96H24, the C1s core-level DOS spectrum in the binding
energy range the can distinguish only the Carbon atoms, which are located on the periphery of the
molecule, from the atoms of the inner part of the molecule. The established difference in the C1s
core-level DOS spectra in the binding energy range for GNF C96 (M=5) and PAH C96H24 is
obviously caused by the presence of two weakly bound π-systems in GNF and one conjugated
system in PAH.
The C1s core-level DOS spectrum of the nanoflakeC96-2(1) is somewhat more complex than
the spectrum of the nanoflakeC96-1(1) with a single vacancy. This is reflected both in a greater
number of intensity maxima and in a significant overlap of the Gaussian functions, on which the
spectrum was fitted. If for nanoflake C96-1(1) three degenerate MOs are localized on all three doubly
coordinated Carbon atoms surrounding the single vacancy, then for nanoflake C96-2(1) the situation
is somewhat different. In particular, the MO with the lowest energy is localized on Carbon atoms
concentrated around two single vacancies, and they correspond to the peak with an energy of -
286.36 eV.
The C1s core-level DOS spectrum of PAH C96-2(1)H24(M=5) in the binding energy range
differs from the similar spectrum of the system C96-1(1)H24 (M=3) by the presence of one additional
75
peak with a low intensity with a binding energy of -284.78 eV. This peak refers to the C1s states
of unsaturated Carbon atoms that surround each of the single vacancies.
The analysis of the C1s core-level DOS distributions of the GNF C96 (M=5) and PAH
C96H24, as well as their defect-containing derivatives allows to identification of different types of
Carbon atoms depending on the degree of hybridization of their atomic orbitals, the availability of
vacancies and, to some extent, their position in the nanoflake.
References
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10. Yamada Y., Kim J., Matsuo S., Sato S. Nitrogen-containing graphene analyzed by X-ray
photoelectron spectroscopy. Carbon. 2014. 70: 59.
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11. Yamada Y., Yasuda H., Murota K., Nakamura M, Sodesawa T., Sato S. Analysis of heat-
treated graphite oxide by X-ray photoelectron spectroscopy. J. Mater. Sci. 2013. 48: 8171.
https://doi.org/10.1007/s10853-013-7630-0
Література
1. Karpenko O.S., LobanovV.V., Kartel M.Т. Properties of hexagon-shaped carbon
nanoclusters// Хімія, фізика та технологія поверхні. – 2013. – Т.4, №2. – С. 123–131.
2. Карпенко О.С. ЛобановВ.В., КартельН.Т. Строение и свойства углеродных
нанокластеров гексагональной формы, содержащих одну и две моновакансии //
Поверхность: Сб. научных тр. / Ин-т химии поверхности им. А.А. Чуйко НАН
Украины; отв. ред. Н.Т. Картель. – Киев: ООО «Интерсервис», 2013. – Вып. 5(20). –
С. 14–25.
3. Карпенко О.С. Лобанов В.В., Картель Н.Т. Cтроение и свойства гексагональних
углеродных нанокластеров C95N графеноподобной структуры // Хімія, фізика та
технологія поверхні. – 2016. – Т.7, №2. – С. 157–166.
76
4. KartelM.T., KarpenkoO.S., LobanovV.V., BoW. Reactivity of defect-free and vacancy-
containing hexagonal graphene nanoclusters according to quantum chemistry approach //
International Journal of Current Research (IJCR). – 2017. – V. 9, Iss. 8. – P. 55598–55605.
5. Schmidt M.W., Baldridge K.K., Boatz J.A. et al. General atomic and molecular electronic
structure system // J. Comput. Chem. – 1993. – V. 14,Iss. 11. – P. 1347–1363.
6. Kohn W., Sham L.S. Self-consistent equation including exchange and correlation effect //
Phys. Rev. A. – 1965. – V. 140, N 4. – P. 1133–1138.
7. Parr R.G., Yang W. Density-functional theory of atoms and molecules. – Oxford: Oxford
Univ. Press, 1989. – 333 p.
8. Becke A.D. Density-functional thermochemistry. III. The role of exchange // J. Chem. Phys.
– 1993. – V. 98. – P. 5648–5652.
9. Lee C., Yang W., Parr R.G. Development of the Colle-Salvetti correlation-energy formula
into a functional of the electron density // Phys. Rev. B. – 1988. – V. 37, No 2. – P. 785–
789.
10. Yamada Y., Kim J., Matsuo S., Sato S. Nitrogen-containing graphene analyzed by X-ray
photoelectron spectroscopy // Carbon. – 2014. – V. 70. – P. 59–74.
11. Yamada Y., Yasuda H., Murota K., Nakamura M,. Sodesawa T., Sato S. An alysis of heat-
treated graphit eoxide by X-ray photo electron spectroscopy // J. Mater. Sci. – 2013. – V. 48.
– P. 8171–8198.
ЗАЛЕЖНІСТЬ ГУСТИНИ ОСТОВНИХ
ОДНОЕЛЕКТРОННИХ СТАНІВ АТОМІВ КАРБОНУ (C1s)
ВІД ЇХ ПОЛОЖЕННЯ У ВУГЛЕЦЕВОМУ НАНОКЛАСТЕРІ
С96 ТА У ПОЛІАРОМАТИЧНІЙ МОЛЕКУЛІ С96Н24
О.С. Карпенко, В.В. Лобанов, М.Т. Картель
Інститут хімії поверхні ім. О.О. Чуйка Національної академії наук України,
вул. Генерала Наумова, 17, Київ, 03164, Україна, e-mail: karpenkooksana@ukr.net
Вуглецеві нанокластери (ВНК) гексагональної форми, обмежені тільки
зигзагоподібними краями з двократно та трикратно координованими атомами Карбону,
володіють підвищеною реакційною здатністю. Не дивлячись на високу симетрію (D6h)
таких систем, атоми Карбону в них займають нееквівалентні позиції. У зв’язку з цим
постає питання щодо визначення таких їх фізико-хімічних характеристик, чисельне
значення яких можна пов’язати з положенням у кластері. Наявність такої
характеристики разом з простотою її обчислення дає змогу передбачити властивості
нанокластерів одержаних з ВНК, введенням в них одно- та багатоатомних вакансій, або
заміщенням атомів Карбону електронодонорними чи електроноакцепторними атомами.
До такої характеристики відноситься спектр одноелектронних енергій, максимуми в
якому однозначно характеризують атоми Карбону певного типу.
Пропонована робота присвячена квантовохімічним розрахункам спектрів одно-
електронних енергій ВНК С96 гексагональної форми в основному квінтетному
(мултиплетність, М=5) електронному стані та аналогічної за будовою поліароматичної
молекули (ПАМ) С96Н24, а також їх похідних з однією та двома моновакансіями. Усі
розрахунки виконані методом теорії функціоналу електронної густини із залученням
валентно-розщепленого базисного набору 6-31 G(d, p). Системи з відкритими оболонками
розглядалися з використанням обмінно-кореляційного функціоналу UB3LYP. Одержані
спектри розкладалися по набору гаусових функцій.
77
Розкладання по гаусовим функціям теоретично розрахованого спектра одно-
електронних станів в області енергії остовного рівня С1s засвідчив про наявність шести
піків, кожен з яких можна віднести до певного типу атомів Карбону. Пік з найвищою
енергією зв’язування (-285.57 еВ) зумовлений внесками від С1s остовного стану двократно
координованих атомів Карбону крайового циклічного ланцюжка. С1s орбіталі атомів
центрального гексагона (ЦГ) та I циклічного ланцюжка утворюють делокалізовані в різних
ділянках кластера молекулярні орбіталі (МО).
Аналогічний спектр ПАМ С96Н24 дещо зсунутий в область нижчих енергій
зв’язування остовного С1s-електрона і містить лише два чітко визначених піки. Пік з
вищою енергією зв’язування (-284.36 еВ) породжується 1s-станами атомів ЦГ та
атомами I циклічного ланцюжка, які зв’язані з атомами ЦГ.
Встановлена відмінність у спектрах густини одно-електронних станів в інтервалі
енергії остовного рівня С1s для ВНК С96 (М=5) та ПАМ С96Н24, очевидно, обумовлена
наявністю двох слабко зв’язаних π-систем в першому з них та однієї кон’югованої системи
в ПАМ.
Спектр густини одно-електронних станів дефектвмісного кластера С96-1(1) (М=3)
(з кластера С96 видалено один атом ЦГ) породжується станом С1s атомів Карбону II
циклічного ланцюга, які розміщуються на різних відстанях від центру кластера. Пік
найнижчої інтенсивності (-284.63 еВ) виникає у спектрі як відображення появи у кластері
С96-1(1) двократно координованих атомів Карбону, які оточують моно вакансію.
Із аналізу спектра густини одноелектронних станів кластера С96-2(1) в інтервалі
енергії остовного рівня С1s видно, що двократно координовані атоми Карбону,
зосереджені навколо двох моновакансій, суттєво нееквівалентні. Якщо на двох з них
локалізована МО з найнижчою енергією зв'язування, то на третіх атомах, по одному
навколо кожної моновакансії, – з найвищою.
Спектр одноелектронних станів дефектвмісних молекулярних систем з однією
С96-1(1)Н24 та двома С96-2(1)Н24моновакансіями подібні до аналогічного спектра ПАМ С96Н24.
В першому з них з’являється один додатковій максимум, обумовлений С1s атомів, які
оточують моновакансію. В другому спектрі присутні два додаткових максимуми, кожен
з яких породжується остовними С1s станами атомів, сусідніх з індивідуальними
вакансіями.
Ключові слова: графеноподібні нанокластери гексагональної форми, поліциклічний
ароматичний вуглеводень, густина електронних станів, зсув C1s остовного рівня, теорія
функціоналу густини, дефектвмісний нанокластер, моновакансія, гаусова апроксимація
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| id | oai:ojs.pkp.sfu.ca:article-746 |
| institution | Surface |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2025-09-24T17:45:58Z |
| publishDate | 2022 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | surfacezbircomua/c9/71f8d0a0fb7174fc92002a84532312c9.pdf |
| spelling | oai:ojs.pkp.sfu.ca:article-7462023-04-20T10:24:32Z C1s core-level binding energy shift dependence from carbon atoms position in graphenenanoflakes C96 and polycyclic aromatic hydrocarbon C96H24: a dft study Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 Карпенко, О. С. Лобанов, В. В. Картель, М. Т. hexagon-shape graphene nanoflake(GNF) polycyclic aromatic hydrocarbon (PAH) electronic density of states (DOS) C1s core-level shift, density functional theory (DFT) ), defect-containing nanoflake single vacancy Gaussian curve fitting графеноподібні нанокластери гексагональної форми поліциклічний ароматичний вуглеводень густина електронних станів зсув C1s остовного рівня теорія функціоналу густини дефектвмісний нанокластер моновакансія гаусова апроксимація The hexagon-shape graphene nanoflakes (GNFs) limited by zigzag edges only (with doubly and triply coordinated atoms) have unique increased reactivity. Despite the high systems symmetry (D6h) the Carbon atoms in GNFs occupy non-equivalent positions. Can such physical and chemical characteristics of GNFs, which depend of the atom position in the cluster, definition? This characteristic together with the simplicity of its calculation makes it possible to predict the properties of nanoflakes obtained from GNFs by introducing single and multiatomic vacancies into them or by replacing Carbon atoms with electron withdrawing and electron donating atoms. This characteristic includes the C1s core-level binding energy shifts, the maxima of which characterize the C atoms of a certain type. The proposed work is devoted to quantum chemical calculations of the electronic density of states (DOS) of pristine hexagon-shape GNF C96 (multiplicity, M=5), their saturated counterpart –polycyclic aromatic hydrocarbon(PAH) C96H24 (M=1) and their derivatives with one and two single vacancies in the ground electronic state (GES). All calculations were performed using the density functional theory (DFT) method with the involvement of the valence-split basis set 6-31G (d,p). Systems with open shells were considered using the UB3LYP exchange-correlation functional. The obtained spectra were fitted using Gaussian curve fitting program to determine the binding energy for each peak. The Gaussian function distribution of the theoretically calculated C1s core-level binding energy shifts of GNFs testified the presence of six peaks, each of which refers to a certain type of Carbon atoms. The C1s peak with the highest binding energy (-285.57 eV) is caused by contributions from the doubly coordinated edge cyclic chain (ECC) Carbon atoms. The C1s orbitals of the central hexagon (CHex) atoms and the first cyclic chain (FCC) atoms form delocalized molecular orbitals (MOs) in different parts of the cluster. The analogous spectrum of PAH C96H24 is slightly shifted to the region of lower binding energies  and  contains  only  two well-defined  peaks.  The peak  with  a higher binding energy (-284.36 eV) is generated by the 1s states of the CHex atoms and the atoms of the FCC, which are bounded to the CHex atoms. The electronic DOS difference in C1s core-level spectra of GNF C96 (M=5) and their saturated counterpart PAH C96H24 is established due to the presence of two weakly bounded π-systems in GNF and common conjugated system in PAH. The electronic DOS of defect-containing cluster C96-1(1) (M=3) (one CHex atom has been removed from the C96nanoflake) is generated by the C1s core-level atoms of the second cyclic chain (SCC), which are located at the different distances from the center of the nanoflake. The peak of the lowest intensity (-284.63 eV) appears in the spectrum as a reflection of the appearance  of  doubly  coordinated  Carbon  atoms  surrounding  the  single  vacancy in the C96-1(1) nanoflake. The analysis of the electronic DOS of the C1s core-level spectrum of the C96-2(1) nanoflakeis shown, that doubly coordinated Carbon atoms, concentrated around two single vacancies, are essentially non-equivalent. If the MO with the lowest binding energy is localized on two of them – the MO with the highest binding energy is localized on the third atoms (one around each single vacancy). The electronic C1s core-level DOS spectrum of defect-containing molecular systems with one C96-1(1)H24 and two C96‑2(1)H24 single vacancies are similar to the analogous spectrum of PAH C96H24. In the first of them – one additional maximum appears due to C1s atoms surrounding the single vacancy. In the second – there are two additional maxima, each of which is generated by C1s core-level atoms adjacent to individual vacancies. Вуглецеві нанокластери (ВНК) гексагональної форми, обмежені тільки зигзагоподібними краями з двократно та трикратно координованими атомами Карбону, володіють підвищеною реакційною здатністю. Не дивлячись на високу симетрію (D6h) таких систем, атоми Карбону в них займають нееквівалентні позиції. У зв’язку з цим постає питання щодо визначення таких їх фізико-хімічних характеристик, чисельне значення яких можна пов’язати з положенням у кластері. Наявність такої характеристики разом з простотою її обчислення дає змогу передбачити властивості нанокластерів одержаних з ВНК, введенням в них одно- та багатоатомних вакансій, або заміщенням атомів Карбону електронодонорними чи електроноакцепторними атомами. До такої характеристики відноситься спектр одноелектронних енергій, максимуми в якому однозначно характеризують атоми Карбону певного типу. Пропонована робота присвячена квантовохімічним розрахункам спектрів одно-електронних енергій ВНК С96 гексагональної форми в основному квінтетному (мултиплетність, М=5) електронному стані та аналогічної за будовою поліароматичної молекули (ПАМ) С96Н24, а також їх похідних з однією та двома моновакансіями. Усі розрахунки виконані методом теорії функціоналу електронної густини із залученням валентно-розщепленого базисного набору 6-31 G(d, p). Системи з відкритими оболонками розглядалися з використанням обмінно-кореляційного функціоналу UB3LYP. Одержані спектри розкладалися по набору гаусових функцій. Розкладання по гаусовим функціям теоретично розрахованого спектра одно-електронних станів в області енергії остовного рівня С1s засвідчив про наявність шести піків, кожен з яких можна віднести до певного типу атомів Карбону. Пік з найвищою енергією зв’язування (-285.57 еВ) зумовлений внесками від С1s остовного стану двократно координованих атомів Карбону крайового циклічного ланцюжка. С1s орбіталі атомів центрального гексагона (ЦГ) та I циклічного ланцюжка утворюють делокалізовані в різних ділянках кластера молекулярні орбіталі (МО). Аналогічний спектр ПАМ С96Н24 дещо зсунутий в область нижчих енергій зв’язування остовного С1s-електрона і містить лише два чітко визначених піки. Пік з вищою енергією зв’язування (-284.36 еВ) породжується 1s-станами атомів ЦГ та атомами I циклічного ланцюжка, які зв’язані з атомами ЦГ. Встановлена відмінність у спектрах густини одно-електронних станів в інтервалі енергії остовного рівня С1s для ВНК С96 (М=5) та ПАМ С96Н24, очевидно, обумовлена наявністю двох слабко зв’язаних π-систем в першому з них та однієї кон’югованої системи в ПАМ. Спектр густини одно-електронних станів дефектвмісного кластера С96-1(1) (М=3) (з кластера С96 видалено один атом ЦГ) породжується станом С1s атомів Карбону II циклічного ланцюга, які розміщуються на різних відстанях від центру кластера. Пік найнижчої інтенсивності (-284.63 еВ) виникає у спектрі як відображення появи у кластері С96-1(1) двократно координованих атомів Карбону, які оточують моно вакансію. Із аналізу спектра густини одноелектронних станів кластера С96-2(1) в інтервалі енергії остовного рівня С1s видно, що двократно координовані атоми Карбону, зосереджені навколо двох моновакансій, суттєво нееквівалентні. Якщо на двох з них локалізована МО з найнижчою енергією зв'язування, то на третіх атомах, по одному навколо кожної моновакансії, – з найвищою. Спектр одноелектронних станів дефектвмісних молекулярних систем з однією С96‑1(1)Н24 та двома С96‑2(1)Н24моновакансіями подібні до аналогічного спектра ПАМ С96Н24. В першому з них з’являється один додатковій максимум, обумовлений С1s атомів, які оточують моновакансію. В другому спектрі присутні два додаткових максимуми, кожен з яких породжується остовними С1s станами атомів, сусідніх з індивідуальними вакансіями. Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2022-11-30 Article Article application/pdf https://surfacezbir.com.ua/index.php/surface/article/view/746 10.15407/Surface.2022.14.063 Surface; No. 14(29) (2022): Surface; 63-77 Поверхность; № 14(29) (2022): Поверхня; 63-77 Поверхня; № 14(29) (2022): Поверхня; 63-77 3154-8091 3154-8083 10.15407/Surface.2022.14 en https://surfacezbir.com.ua/index.php/surface/article/view/746/740 Авторське право (c) 2022 О.С. Карпенко, В.В. Лобанов, М.Т. Картель |
| spellingShingle | графеноподібні нанокластери гексагональної форми поліциклічний ароматичний вуглеводень густина електронних станів зсув C1s остовного рівня теорія функціоналу густини дефектвмісний нанокластер моновакансія гаусова апроксимація Карпенко, О. С. Лобанов, В. В. Картель, М. Т. Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title | Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title_alt | C1s core-level binding energy shift dependence from carbon atoms position in graphenenanoflakes C96 and polycyclic aromatic hydrocarbon C96H24: a dft study |
| title_full | Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title_fullStr | Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title_full_unstemmed | Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title_short | Залежність густини остовних одноелектронних станів атомів карбону (C1s) від їх положення у вуглецевому нанокластері С96 та у поліароматичній молекулі С96Н24 |
| title_sort | залежність густини остовних одноелектронних станів атомів карбону (c1s) від їх положення у вуглецевому нанокластері с96 та у поліароматичній молекулі с96н24 |
| topic | графеноподібні нанокластери гексагональної форми поліциклічний ароматичний вуглеводень густина електронних станів зсув C1s остовного рівня теорія функціоналу густини дефектвмісний нанокластер моновакансія гаусова апроксимація |
| topic_facet | hexagon-shape graphene nanoflake(GNF) polycyclic aromatic hydrocarbon (PAH) electronic density of states (DOS) C1s core-level shift density functional theory (DFT) ) defect-containing nanoflake single vacancy Gaussian curve fitting графеноподібні нанокластери гексагональної форми поліциклічний ароматичний вуглеводень густина електронних станів зсув C1s остовного рівня теорія функціоналу густини дефектвмісний нанокластер моновакансія гаусова апроксимація |
| url | https://surfacezbir.com.ua/index.php/surface/article/view/746 |
| work_keys_str_mv | AT karpenkoos c1scorelevelbindingenergyshiftdependencefromcarbonatomspositioningraphenenanoflakesc96andpolycyclicaromatichydrocarbonc96h24adftstudy AT lobanovvv c1scorelevelbindingenergyshiftdependencefromcarbonatomspositioningraphenenanoflakesc96andpolycyclicaromatichydrocarbonc96h24adftstudy AT kartelʹmt c1scorelevelbindingenergyshiftdependencefromcarbonatomspositioningraphenenanoflakesc96andpolycyclicaromatichydrocarbonc96h24adftstudy AT karpenkoos zaležnístʹgustiniostovnihodnoelektronnihstanívatomívkarbonuc1svídíhpoložennâuvuglecevomunanoklasterís96taupolíaromatičníjmolekulís96n24 AT lobanovvv zaležnístʹgustiniostovnihodnoelektronnihstanívatomívkarbonuc1svídíhpoložennâuvuglecevomunanoklasterís96taupolíaromatičníjmolekulís96n24 AT kartelʹmt zaležnístʹgustiniostovnihodnoelektronnihstanívatomívkarbonuc1svídíhpoložennâuvuglecevomunanoklasterís96taupolíaromatičníjmolekulís96n24 |