期刊
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
卷 110, 期 2, 页码 406-415出版社
WILEY-BLACKWELL
DOI: 10.1002/qua.22301
关键词
density functional theory; hybrid functionals; aluminosilicates; vibrational spectrum; local basis set
The performance of eleven DFT functionals in describing the equilibrium structure and the vibrational spectra at the Gamma point of pyrope (Mg3Al2Si3O12), forsterite (alpha-Mg2SiO4), alpha-quartz (alpha-SiO2) and corundum (alpha-Al2O3) is discussed. The four systems, for which accurate experimental data are available, are here used as a representative sample of the large aluminosilicates family. Calculations were performed with the periodic ab initio CRYSTAL code by using all-electron Gaussian-type basis sets. All the functionals here considered provide reasonable structural predictions, the hybrid PBE0 giving the least deviation from the experimental unit cell volumes (from -0.3% to +0.6%). At the other extreme, SVWN and SPWLSD (similar or equal to -3%) And PBE and PW91 (similar or equal to +3%) provide the largest volume under- and over-estimation, respectively. Vibrational frequencies are more accurate when computed with hybrid functionals, with the best performance provided by B3LYP and WC1LYP (mean absolute differences with respect to experiments evaluated on a set of 134 vibrational frequencies, vertical bar(Delta) over bar vertical bar similar or equal to 5.5 cm(-1)). The three recently proposed GGA functionals, PBEsol, SOGGA-PBE and WC-PBE, provide a good description of the vibrational spectra, of the same quality as the one provided by PBE0 and B1WC (vertical bar(Delta) over bar vertical bar(t) similar or equal to 10 cm(-1)), whereas poorer results are obtained with PBE (vertical bar(Delta) over bar vertical bar(t) similar or equal to 17 cm(-1)). (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 110: 406-415, 2010
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