Structure and Frontier Molecular Orbital (FMO) energies of alpha-Keggin-type polyoxometalate [PW12O40](3-): A systematical study with different functionals of density functional theory

摘要

To obtain more reasonable Frontier Molecular Orbital (FMO) energies of alpha-Keggin anion [PW12O40](3-), the influence of different density functional theory (DFT) functionals were systematically investigated. Except LC-omega PBE, M06HF, LC-BLYP, HF and LC-BP86, the functionals we tested overestimate the bond length with mean unsigned error (MUE) values ranging from 0.02 angstrom to 0.03 angstrom. All the functionals used show the typical trend that the FMO energy levels are overestimated. The hybrid generalized gradient approximation (hGGA), such as B3P86 (MUE 0.465 eV), performs better than others. The results on Na3PW12O40 are more reasonable than those of [PW12O40](3-) as the errors caused by the negative charge were compensated. B3P86 is superior to B3PW91 and B3LYP in the description on Na3PW12O40 with MUE 0.461 eV and mean signed error (MSE) 0.043 eV. B3P86 with 13% HF exchange offers the reasonable MUEs (approximate to 0.12 eV) for M3PW12O40, M4SiW12O40 and M6P2W18O62 (M = Na, K). (C) 2016 Elsevier B.V. All rights reserved.