Density functional Gaussian-type-orbital approach to molecular geometries, vibrations, and reaction energies

Abstract

We present the theory, computational implementation, and applications of a density functional Gaussian-type-orbital approach called DGauss. For a range of typical organic and small inorganic molecules, it is found that this approach results in equilibrium geometries, vibrational frequencies, bond dissociation energies, and reaction energies that are in many cases significantly closer to experiment than those obtained with Hartree-Fock theory. On the local spin density functional level, DGauss predicts equilibrium bond lengths within about 0.02 A or better compared with experiment, bond angles, and dihedral angles to within l-2", and vibrational frequencies within about 3%-5%. While Hat-tree-Fock optimized basis sets such as the 6-3 1 G** set can be used in DGauss calculations to give good geometries, the accurate prediction of reaction energies requires the use of density functional optimized Gaussian-type basis sets. Nonlocal corrections as proposed by Becke and Perdew for the exchange and correlation energies are found to be essential in order to predict bond dissociation energies and reaction energies within a few kcal/mol. The computational efficiency of the present method together with its accuracy, which is comparable to correlated Hartree-Fock based methods, promises a great usefulness of the DGauss approach for the study of large and complex molecular structures.

Perspective: Fifty years of density-functional theory in chemical physics

“…Computation of bond energies is therefore one of the greatest concerns of quantum chemists. It was not until the 1980s that software implementations of HFS (and hence KS-DFT) were up to the task of computing accurate molecular energies, [26][27][28] but by the end of the decade robust programs were in place [36][37][38][39] and dissociation energies were under test. The energy required to dissociate a molecule entirely to free atoms, i.e., break all its bonds, is called "atomization" energy.…”

On the accuracy of density functional theory for ion–molecule clusters. A case study of PLn+ clusters of the first and second row hydrides

“…For a wide range of systems DFT has been found to yield properties (geometries, dissociation energies, and frequencies) comparable in quality to the MP2 results (1 I). Also, it has been established that DFT yields accurate reaction energies for several chemical processes (12)(13)(14), when appropriate nonlocal gradient corrections are included. DFT is computationally less demanding than MP2 or other ab initio methods that include electron correlation, especially for large systems.…”

H2-Anion Interactions and Energy Calculations for Imidazolium-based Ionic Liquids as Hydrogen Storage Materials

“…In this work, all the quantum calculations on the structural optimizations, theoretical spectral characteristics, interaction energies with nH 2 and molecular orbitals have been performed using density functional theory (DFT) [25] and Becke's three-parameter exchange function [26] combined with the exchange functional component of Perdew and Wang (B3PW91) [27], 6-31G (d) basis set level. Datta and Pati have reported that the PW91 function provided more successful outcomes than B3LYP related physical adsorption of molecular hydrogen for circulene derivatives [28].…”