Details

Autor(en) / Beteiligte

• Bellonzi, Nicole
• Alguire, Ethan
• Fatehi, Shervin
• Shao, Yihan
• Subotnik, Joseph E.

Titel

TD-DFT spin-adiabats with analytic nonadiabatic derivative couplings

Ist Teil von

• The Journal of chemical physics, 2020-01, Vol.152 (4), p.044112

Ort / Verlag

United States: American Institute of Physics

Erscheinungsjahr

2020

Quelle

American Institute of Physics (AIP) Journals

Beschreibungen/Notizen

• We present an algorithm for efficient calculation of analytic nonadiabatic derivative couplings between spin-adiabatic, time-dependent density functional theory states within the Tamm-Dancoff approximation. Our derivation is based on the direct differentiation of the Kohn-Sham pseudowavefunction using the framework of Ou et al. Our implementation is limited to the case of a system with an even number of electrons in a closed shell ground state, and we validate our algorithm against finite difference at an S1/T2 crossing of benzaldehyde. Through the introduction of a magnetic field spin-coupling operator, we break time-reversal symmetry to generate complex valued nonadiabatic derivative couplings. Although the nonadiabatic derivative couplings are complex valued, we find that a phase rotation can generate an almost entirely real-valued derivative coupling vector for the case of benzaldehyde.