Journal of Computational Chemistry, Год журнала: 2025, Номер 46(8)
Опубликована: Март 25, 2025
De-excitations play a prominent role within the mathematical formalism of time-dependent density functional theory (TDDFT) and other excited-state response methods. However, their physical meaning remains largely unexplored poorly understood. It is purpose this work to shed new light on issue. The main thesis developed here that de-excitations are not peculiarity TDDFT but they more fundamental property underlying wave functions reflecting how electrons excited between partially occupied orbitals. paraquinodimethane (pQDM) molecule chosen as convenient model system whose open-shell character can be modulated via twisting its methylene groups. Using one-electron transition matrix rigorous basis for our analysis, we highlight qualitative quantitative parallels in way reflected multireference function computations. As physically observable consequence, lowering dipole moment derives from destructive interference excitation de-excitation contributions. In summary, hope will formal practical aspects regarding application computations, especially diradicaloid systems.
Язык: Английский