Calculation of non-adiabatic coupling vectors in a local-orbital basis set

Most of today's molecular-dynamics simulations of materials are based on the Born-Oppenheimer approximation. There are many cases, however, in which the coupling of the electrons and nuclei is important and it is necessary to go beyond the Born-Oppenheimer approximation. In these methods, the n...

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Bibliographic Details
Published in:The Journal of chemical physics 2013-04, Vol.138 (15), p.154106-154106
Main Authors: Abad, Enrique, Lewis, James P, Zobač, Vladmír, Hapala, Prokop, Jelínek, Pavel, Ortega, José
Format: Article
Language:English
Subjects:
Born-Oppenheimer approximation
Computational efficiency
Coupling (molecular)
Density
Evolution
Mathematical analysis
Nuclei
Vectors (mathematics)
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Summary:Most of today's molecular-dynamics simulations of materials are based on the Born-Oppenheimer approximation. There are many cases, however, in which the coupling of the electrons and nuclei is important and it is necessary to go beyond the Born-Oppenheimer approximation. In these methods, the non-adiabatic coupling vectors are fundamental since they represent the link between the classical atomic motion of the nuclei and the time evolution of the quantum electronic state. In this paper we analyze the calculation of non-adiabatic coupling vectors in a basis set of local orbitals and derive an expression to calculate them in a practical and computationally efficient way. Some examples of the application of this expression using a local-orbital density functional theory approach are presented for a few simple molecules: H3, formaldimine, and azobenzene. These results show that the approach presented here, using the Slater transition-state density, is a very promising way for the practical calculation of non-adiabatic coupling vectors for large systems.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4801511