Gradients and Non-Adiabatic Derivative Coupling Terms for Spin-Orbit Wavefunctions - Softcover

Belcher, Lachlan T

Softcover

ISBN 10: 1288315716 ISBN 13: 9781288315710

Publisher: Biblioscholar, 2012

Synopsis

Analytic gradients of electronic eigenvalues require one calculation per nuclear geometry, compared to 3n calculations for finite difference methods, where n is the number of nuclei. Analytic non-adiabatic derivative coupling terms, which are calculated in a similar fashion, are used to remove non-diagonal contributions to the kinetic energy operator, leading to more accurate nuclear dynamics calculations than those that employ the Born-Oppenheimer approximation and assume off-diagonal contributions are zero. The current methods and underpinnings for calculating both of these quantities for MRCI-SD wavefunctions in COLUMBUS are reviewed. Before this work, these methods were not available for wavefunctions of a relativistic MRCI-SD Hamiltonian. A formalism for calculating the density matrices, analytic gradients, and analytic derivative coupling terms for those wavefunctions is presented. The results of a sample calculation using a Stuttgart basis for K He are presented.

Edition details

• Publisher: Biblioscholar
• Publication date: 2012
• ISBN 10: 1288315716
• ISBN 13: 9781288315710
• Binding: Paperback
• Language: English
• Number of pages: 230