Вплив методів та базисних наборів на результати розрахунків з використанням різних моделей сольватації

• Date: 2018
• Main Author: Gun'ko, V. M.
• Format: Article
• Language: English
• Published: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2018
• Subjects: ефекти сольватації; моделі сольватації; квантово-хімічні методи; ab initio та ТФГ методи; напівемперічні методи
• Online Access: https://www.cpts.com.ua/index.php/cpts/article/view/450
• Journal Title: Chemistry, Physics and Technology of Surface

Various quantum chemical approaches including ab initio, density functional theory (B3LYP, CAM-B3LYP,     ?B97X-D, M06HF) and semiempirical (PM7) methods with different basis sets and various solvation models (SMD, IEFPCM, COSMO), as well as a supermolecular approach, and the basis set superposition error (BSSE) corrections, used to analyze the solvation effects are compared for polar (water, ethanol, dimethylsulfoxide, acetonitrile, acetone), weakly polar (chloroform) and nonpolar (benzene, n-hexane, carbon tetrachloride) solvents per se and interacting with unmodified and modified silicas. The DFT methods give smaller errors in the DGs values than the PM7 method with various solvation models. For the molecular clusters with water alone or water with organics, the interaction energy decreases with enhanced amorphism of the systems. The supermolecular approach with PM7 gives worse results (in comparison to the experimental data) than those of SMD/PM7 or COSMO/PM7. An increase in the basis sets can give worse results than that at smaller ones because the parameters in the SMD model were calibrated using the experimental data and ab initio or DFT calculations of the same systems with relatively small basis sets.