Self-interaction correction, electrostatic, and structural influences on time-dependent density functional theory excitations of bacteriochlorophylls from the light-harvesting complex 2.
- Resource Type
- Article
- Authors
- Kehrer, Juliana; Richter, Rian; Foerster, Johannes M.; Schelter, Ingo; Kümmel, Stephan
- Source
- Journal of Chemical Physics. 10/14/2020, Vol. 153 Issue 14, p1-11. 11p.
- Subject
- *TIME-dependent density functional theory
*ELECTRIC potential
*MOLECULAR dynamics
*DENSITY functional theory
*CRYSTAL structure
- Language
- ISSN
- 0021-9606
First-principles calculations offer the chance to obtain a microscopic understanding of light-harvesting processes. Time-dependent density functional theory can have the computational efficiency to allow for such calculations. However, the (semi-)local exchange-correlation approximations that are computationally most efficient fail to describe charge-transfer excitations reliably. We here investigate whether the inexpensive average density self-interaction correction (ADSIC) remedies the problem. For the systems that we study, ADSIC is even more prone to the charge-transfer problem than the local density approximation. We further explore the recently reported finding that the electrostatic potential associated with the chromophores' protein environment in the light-harvesting complex 2 beneficially shifts spurious excitations. We find a great sensitivity on the chromophores' atomistic structure in this problem. Geometries obtained from classical molecular dynamics are more strongly affected by the spurious charge-transfer problem than the ones obtained from crystallography or density functional theory. For crystal structure geometries and density-functional theory optimized ones, our calculations confirm that the electrostatic potential shifts the spurious excitations out of the energetic range that is most relevant for electronic coupling. [ABSTRACT FROM AUTHOR]