A comparison of Hartree-Fock, MP2, and DFT results for the HCN dimer and crystal

Alfredsson, Maria and Ojamae, Lars and Hermansson, Kersti (1996) A comparison of Hartree-Fock, MP2, and DFT results for the HCN dimer and crystal. International Journal of Quantum Chemistry, 60 (3). pp. 767-777. ISSN 0020-7608. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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http://dx.doi.org/10.1002/(SICI)1097-461X(1996)60:...

Abstract

A number of hydrogen-bond related quantities-geometries, interaction energies, dipole moments, dipole moment derivatives, and harmonic vibrational frequencies-were calculated at the Hartree-Fock, MP2, and different DFT levels for the HCN dimer and the periodic HCN crystal. The crystal calculations were performed with the Hartree-Fock program CRYSTAL92, which routinely allows an a posteriori electron-correlation correction of the Hartree-Fock obtained lattice energy using different correlation-only functionals. Here, we have gone beyond this procedure by also calculating the electron-correlation energy correction during the structure optimization, i.e., after each CRYSTAL92 Hartree-Fock energy evaluation, the a posteriori density functional scheme was applied. In a similar manner, we optimized the crystal structure at the MP2 level, i.e., for each Hartree-Fock CRYSTAL92 energy evaluation, an MP2 correction was performed by summing the MP2 pair contributions from all HCN molecules within a specified cutoff distance. The crystal cell parameters are best reproduced at the Hartree-Fock and the nongradient-corrected HF + LDA and HF + VWN levels. The BSSE-corrected MP2 method and the HF + P91, HF + LDA, and HF + VWN methods give lattice energies in close agreement with the ZPE-corrected experimental lattice energy. The (HCN), dimer properties are best reproduced at the MP2 level, at the gradient-corrected DFT levels, and with the B3LYP and BHHLYP methods. (C) 1996 John Wiley & Sons, Inc.

Item Type: Article
Subjects: Q Science
Q Science > QD Chemistry
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: Maria Alfredsson
Date Deposited: 04 Dec 2010 23:32
Last Modified: 28 Apr 2014 08:57
Resource URI: https://kar.kent.ac.uk/id/eprint/26106 (The current URI for this page, for reference purposes)
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