Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study

We report here recent study of molecular dynamics simulation of exciton relaxation in several ionic crystals at low temperature. Both the lowest energy spin triplet and some of the low lying hole excited states are allowed to relax in view of studying the radiation defect formation channels. The pre...

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Видавець:Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Дата:2003
Автор: Song, K.S.
Формат: Стаття
Мова:English
Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2003
Назва видання:Физика низких температур
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Онлайн доступ:http://dspace.nbuv.gov.ua/handle/123456789/128923
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Цитувати:Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study / K.S. Song // Физика низких температур. — 2003. — Т. 29, № 9-10. — С. 1001-1006. — Бібліогр.: 10 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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spelling irk-123456789-1289232018-01-15T03:03:04Z Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study Song, K.S. Electronically Induced Phenomena We report here recent study of molecular dynamics simulation of exciton relaxation in several ionic crystals at low temperature. Both the lowest energy spin triplet and some of the low lying hole excited states are allowed to relax in view of studying the radiation defect formation channels. The previously used semi-classical program has been modified to implement the solution of Newton’s equations with 0.48 fs time step. The relaxation of an exciton localized on a single site (as Br⁰ + e, or F⁰ + e, respectively) is studied at 10 K in KBr and in CaF₂. In KBr the triplet self-trapped exciton leads to separated Frenkel pair in about 1–2 ps, followed by slow oscillation of the hole center along the (110) axis. The defect pair created is separated by about 10 Å (third nearest neighbor). In CaF₂, the relaxation reaches the geometry of the nearest Frenkel pair, with the hole center oriented along a (111) axis in about 0.3 ps at 10 K. However, at 80 K the system can undergo further relaxation into a slightly more distant defect pairs. When the hole is excited to higher levels, the molecule bond of the hole center undergoes violent oscillations. In KBr, the hole center is found to form in the second nearest neighbor position within about 0.5 ps. The species formed are, however, different from the well known primary radiation defects. Similar process is also observed in CaF₂. 2003 Article Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study / K.S. Song // Физика низких температур. — 2003. — Т. 29, № 9-10. — С. 1001-1006. — Бібліогр.: 10 назв. — англ. 0132-6414 PACS: 71.35.Aa, 71.15.Pd http://dspace.nbuv.gov.ua/handle/123456789/128923 en Физика низких температур Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Electronically Induced Phenomena
Electronically Induced Phenomena
spellingShingle Electronically Induced Phenomena
Electronically Induced Phenomena
Song, K.S.
Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
Физика низких температур
description We report here recent study of molecular dynamics simulation of exciton relaxation in several ionic crystals at low temperature. Both the lowest energy spin triplet and some of the low lying hole excited states are allowed to relax in view of studying the radiation defect formation channels. The previously used semi-classical program has been modified to implement the solution of Newton’s equations with 0.48 fs time step. The relaxation of an exciton localized on a single site (as Br⁰ + e, or F⁰ + e, respectively) is studied at 10 K in KBr and in CaF₂. In KBr the triplet self-trapped exciton leads to separated Frenkel pair in about 1–2 ps, followed by slow oscillation of the hole center along the (110) axis. The defect pair created is separated by about 10 Å (third nearest neighbor). In CaF₂, the relaxation reaches the geometry of the nearest Frenkel pair, with the hole center oriented along a (111) axis in about 0.3 ps at 10 K. However, at 80 K the system can undergo further relaxation into a slightly more distant defect pairs. When the hole is excited to higher levels, the molecule bond of the hole center undergoes violent oscillations. In KBr, the hole center is found to form in the second nearest neighbor position within about 0.5 ps. The species formed are, however, different from the well known primary radiation defects. Similar process is also observed in CaF₂.
format Article
author Song, K.S.
author_facet Song, K.S.
author_sort Song, K.S.
title Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
title_short Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
title_full Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
title_fullStr Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
title_full_unstemmed Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study
title_sort exciton relaxation in kbr and caf₂ at low temperature: molecular dynamics study
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
publishDate 2003
topic_facet Electronically Induced Phenomena
url http://dspace.nbuv.gov.ua/handle/123456789/128923
citation_txt Exciton relaxation in KBr and CaF₂ at low temperature: molecular dynamics study / K.S. Song // Физика низких температур. — 2003. — Т. 29, № 9-10. — С. 1001-1006. — Бібліогр.: 10 назв. — англ.
series Физика низких температур
work_keys_str_mv AT songks excitonrelaxationinkbrandcaf2atlowtemperaturemoleculardynamicsstudy
first_indexed 2023-10-18T20:56:27Z
last_indexed 2023-10-18T20:56:27Z
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