Use of Density Functional Based Tight Binding Methods in Vibrational Circular Dichroism.
J Phys Chem A
; 122(49): 9435-9445, 2018 Dec 13.
Article
em En
| MEDLINE
| ID: mdl-30452264
ABSTRACT
Vibrational circular dichroism (VCD) is a spectroscopic technique used to resolve the absolute configuration of chiral systems. Obtaining a theoretical VCD spectrum requires computing atomic polar and axial tensors on top of the computationally demanding construction of the force constant matrix. In this study we evaluated a VCD model in which all necessary quantities are obtained with density functional based tight binding (DFTB) theory. The analyzed DFTB parametrizations fail at providing accurate vibrational frequencies and electric dipole gradients but yield reasonable normal modes at a fraction of the computational cost of density functional theory (DFT). Thus, by applying DFTB in composite methods along with DFT, we show that it is possible to obtain accurate VCD spectra at a much lower computational demand.
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MEDLINE
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En
Ano de publicação:
2018
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Article