Derivative couplings between TDDFT excited states obtained by direct differentiation in the Tamm-Dancoff approximation

Journal Article · Mon Jul 14 04:00:00 EDT 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4887256· OSTI ID:22308575

Ou, Qi; Fatehi, Shervin; Alguire, Ethan; Shao, Yihan ^[1]

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1. Q-Chem, Inc., 6601 Owens Drive, Suite 105, Pleasanton, California 94588 (United States)

Working within the Tamm-Dancoff approximation, we calculate the derivative couplings between time-dependent density-functional theory excited states by assuming that the Kohn-Sham superposition of singly excited determinants represents a true electronic wavefunction. All Pulay terms are included in our derivative coupling expression. The reasonability of our approach can be established by noting that, for closely separated electronic states in the infinite basis limit, our final expression agrees exactly with the Chernyak-Mukamel expression (with transition densities from response theory). Finally, we also validate our approach empirically by analyzing the behavior of the derivative couplings around the T{sub 1}/T{sub 2} conical intersection of benzaldehyde.

• OSTI ID: 22308575
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 2 Vol. 141; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
BENZALDEHYDE
COUPLINGS
DENSITY FUNCTIONAL METHOD
EXCITED STATES
WAVE FUNCTIONS