Journal ArticleDOI
Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields
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In this article, the unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio using DFT, MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set.Abstract:
: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jgread more
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A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
TL;DR: The revised DFT-D method is proposed as a general tool for the computation of the dispersion energy in molecules and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems.
Journal ArticleDOI
Semiempirical GGA-type density functional constructed with a long-range dispersion correction.
TL;DR: A new density functional of the generalized gradient approximation (GGA) type for general chemistry applications termed B97‐D is proposed, based on Becke's power‐series ansatz from 1997, and is explicitly parameterized by including damped atom‐pairwise dispersion corrections of the form C6 · R−6.
Journal ArticleDOI
The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals
Yan Zhao,Donald G. Truhlar +1 more
TL;DR: The M06-2X meta-exchange correlation function is proposed in this paper, which is parametrized including both transition metals and nonmetals, and is a high-non-locality functional with double the amount of nonlocal exchange.
Journal ArticleDOI
QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials
Paolo Giannozzi,Stefano Baroni,Stefano Baroni,Nicola Bonini,Matteo Calandra,Roberto Car,Carlo Cavazzoni,Davide Ceresoli,Guido L. Chiarotti,Matteo Cococcioni,Ismaila Dabo,Andrea Dal Corso,Andrea Dal Corso,Stefano de Gironcoli,Stefano de Gironcoli,Stefano Fabris,Stefano Fabris,Guido Fratesi,Ralph Gebauer,Ralph Gebauer,Uwe Gerstmann,Christos Gougoussis,Anton Kokalj,Michele Lazzeri,Layla Martin-Samos,Nicola Marzari,Francesco Mauri,Riccardo Mazzarello,Stefano Paolini,Alfredo Pasquarello,Lorenzo Paulatto,Lorenzo Paulatto,Carlo Sbraccia,Sandro Scandolo,Sandro Scandolo,Gabriele Sclauzero,Gabriele Sclauzero,Ari P. Seitsonen,Alexander Smogunov,Paolo Umari,Renata M. Wentzcovitch +40 more
TL;DR: QUANTUM ESPRESSO as discussed by the authors is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave).
Journal ArticleDOI
Effect of the damping function in dispersion corrected density functional theory
TL;DR: It is shown by an extensive benchmark on molecular energy data that the mathematical form of the damping function in DFT‐D methods has only a minor impact on the quality of the results and BJ‐damping seems to provide a physically correct short‐range behavior of correlation/dispersion even with unmodified standard functionals.
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AB INITIO Molecular Orbital Theory
TL;DR: In this paper, the use of theoretical models as an alternative to experiment in making accurate predictions of chemical phenomena is discussed, and the formulation of theoretical molecular orbital models starting from quantum mechanics is discussed.