First order nonadiabatic coupling matrix elements between excited states: Implementation and application at the TD-DFT and pp-TDA levels

• Published in: The Journal of chemical physics Vol. 141; no. 24; p. 244105
• Main Authors: Li, Zhendong, Suo, Bingbing, Liu, Wenjian
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 28.12.2014
• Subjects: ALGORITHMS; APPROXIMATIONS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COUPLING; Coupling (molecular); DENSITY FUNCTIONAL METHOD; Density functional theory; EXCITED STATES; IMPLEMENTATION; INTERNAL CONVERSION; LAGRANGIAN FUNCTION; MATRIX ELEMENTS; MOLECULES; Physics; TIME DEPENDENCE
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/1.4903986

The recently proposed rigorous yet abstract theory of first order nonadiabatic coupling matrix elements (fo-NACME) between electronically excited states [Z. Li and W. Liu, J. Chem. Phys. 141, 014110 (2014)] is specified in detail for two widely used models: The time-dependent density functional theory and the particle-particle Tamm-Dancoff approximation. The actual implementation employs a Lagrangian formalism with atomic-orbital based direct algorithms, which makes the computation of fo-NACME very similar to that of excited-state gradients. Although the methods have great potential in investigating internal conversions and nonadiabatic dynamics between excited states of large molecules, only prototypical systems as a first pilot application are considered here to illustrate some conceptual aspects.