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Ab initio absorption spectrum of NiO combining molecular dynamics with the embedded cluster approach in a discrete reaction field

We developed a procedure that combines three complementary computational methodologies to improve the theoretical description of the electronic structure of nickel oxide. The starting point is a Car-Parrinello molecular dynamics simulation to incorporate vibrorotational degrees of freedom into the material model. By means of complete active space self-consistent field second-order perturbation theory (CASPT2) calculations on embedded clusters extracted from the resulting trajectory, we describe localized spectroscopic phenomena on NiO with an efficient treatment of electron correlation. The inclusion of thermal motion into the theoretical description allows us to study electronic transitions that, otherwise, would be dipole forbidden in the ideal structure and results in a natural reproduction of the band broadening. Moreover, we improved the embedded cluster model by incorporating self-consistently at the complete active space self-consistent field (CASSCF) level a discrete (or direct) reaction field (DRF) in the cluster surroundings. The DRF approach offers an efficient treatment of electric response effects of the crystalline embedding to the electronic transitions localized in the cluster. We offer accurate theoretical estimates of the absorption spectrum and the density of states around the Fermi level of NiO, and a comprehensive explanation of the source of the broadening and the relaxation of the charge transfer states due to the adaptation of the environment

© Physical Review B, 2012, vol. 85, núm. 15, p. 155143

American Physical Society

Author: Domingo Toro, Alex
Rodríguez Fortea, Antonio
Swart, Marcel
Graaf, Coen de
Broer, Ria
Date: 2012
Abstract: We developed a procedure that combines three complementary computational methodologies to improve the theoretical description of the electronic structure of nickel oxide. The starting point is a Car-Parrinello molecular dynamics simulation to incorporate vibrorotational degrees of freedom into the material model. By means of complete active space self-consistent field second-order perturbation theory (CASPT2) calculations on embedded clusters extracted from the resulting trajectory, we describe localized spectroscopic phenomena on NiO with an efficient treatment of electron correlation. The inclusion of thermal motion into the theoretical description allows us to study electronic transitions that, otherwise, would be dipole forbidden in the ideal structure and results in a natural reproduction of the band broadening. Moreover, we improved the embedded cluster model by incorporating self-consistently at the complete active space self-consistent field (CASSCF) level a discrete (or direct) reaction field (DRF) in the cluster surroundings. The DRF approach offers an efficient treatment of electric response effects of the crystalline embedding to the electronic transitions localized in the cluster. We offer accurate theoretical estimates of the absorption spectrum and the density of states around the Fermi level of NiO, and a comprehensive explanation of the source of the broadening and the relaxation of the charge transfer states due to the adaptation of the environment
Format: application/pdf
ISSN: 1539-3755 (versió paper)
1550-2376 (versió electrònica)
Document access: http://hdl.handle.net/10256/7611
Language: eng
Publisher: American Physical Society
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1103/PhysRevB.85.155143
Articles publicats (D-Q)
Is part of: © Physical Review B, 2012, vol. 85, núm. 15, p. 155143
Rights: Tots els drets reservats
Subject: Fisicoquímica
Química quàntica
Quantum chemistry
Chemistry, Physical and theorical
Dinàmica molecular -- Simulació per ordinador
Molecular dynamics -- Computer simulation
Title: Ab initio absorption spectrum of NiO combining molecular dynamics with the embedded cluster approach in a discrete reaction field
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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