A Fermi smearing variant of the Tamm–Dancoff approximation for nonadiabatic dynamics involving S1–S0 transitions: Validation and application to azobenzene

Peters, Laurens D. M. ; Kussmann, Jörg and Ochsenfeld, Christian (2020): A Fermi smearing variant of the Tamm–Dancoff approximation for nonadiabatic dynamics involving S1–S0 transitions: Validation and application to azobenzene. In: The Journal of Chemical Physics, Vol. 153, No. 9, 094104

Abstract

The main shortcoming of time-dependent density functional theory (TDDFT) regarding its use for nonadiabatic molecular dynamics (NAMD) is its incapability to describe conical intersections involving the ground state. To overcome this problem, we combine Fermi smearing (FS) DFT with a fractional-occupation variant of the Tamm–Dancoff approximation (TDA) of TDDFT in the generalized gradient approximation. The resulting method (which we denote as FS-TDA) gives access to ground- and excited-state energies, gradients, and nonadiabatic coupling vectors, which are physically correct even in the vicinity of S1–S0 conical intersections. This is shown for azobenzene, a widely used photoswitch, via single point calculations and NAMD simulations of its cis–trans photoisomerization. We conclude that FS-TDA may be used as an efficient alternative to investigate these processes.

• Item Type: Journal article
• EU Funded Grant Agreement Number: 765739
• EU Projects: Horizon 2020 > Marie Skłodowska Curie Actions > Marie Skłodowska-Curie Innovative Training Networks > 765739: COSINE - Training network for COmputational Spectroscopy In Natural sciences and Engineering
• Form of publication: Publisher's Version
• Keywords: Nonadiabatic dynamics, density functional theory, fractional occupations, conical intersections, static correlation
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 530 Physics; 500 Science > 540 Chemistry
• Language: English