Structural or population dynamics: what is revealed by the time-resolved photoelectron spectroscopy of 1,3-cyclohexadiene? A study with an ensemble density functional theory method

Abstract

Time-resolved photoelectron spectra during the photochemical ring-opening reaction of 1,3-cyclohexadiene (CHD) are modeled by an ensemble density functional theory (eDFT) method. The computational methodology employed in this work is capable...

Recent advances in ensemble density functional theory and linear response theory for strong correlation

“…In a number of practical applications to the excited state dynamics of realistic molecular systems, the REKS methodology has demonstrated its accuracy and predictive ability. [29][30][31][32][33][34][35][36][37][38] Although the current implementation of the REKS methodology is not free of certain limitations, these limitations will be removed in the near future and this should considerably improve the prospects of practical use of the method. 27,80 Yet another prospective direction of extending capabilities of the method is in formulating new approaches to obtaining physically observable properties of the strongly correlated systems.…”

“…The EKT-SSR approach 93,94 is capable of providing the information necessary to simulate theoretically the photoelectron spectra (PES) and the time-resolved PES (TRPES). 36,38…”

“…125 In ref. 36, the TRPE spectrum of CHD during the photodynamics was simulated using the EKT-SSR method, see Figure 7. To ensure that the methodology is able to produce the accurate TRPE spectra, the static PE spectra of CHD and HT in the ground electronic states were simulated first.…”

“…Later on, the REKS methodology was extended to incorporate the excited states [23][24][25][26][27] and the resulting methodology enabled computation of the real crossings (conical intersections) between the ground and excited electronic states, 24 which were not achievable with the use of the conventional DFT approaches. 28 This opened up a perspective of describing the excited state dynamics of real molecular systems [29][30][31][32][33][34][35][36][37][38] with the precision matching and even exceeding that of the multiconfigurational wave function methods.…”

Computation of Molecular Electron Affinities Using an Ensemble Density Functional Theory Method

“…Recently, a new method of computing the molecular IPs was proposed by us, where the IPs of the ground and excited electronic states are calculated using the extended Koopmans’ theorem (EKT) , in connection with an ensemble DFT (eDFT) method. The spin-restricted ensemble-referenced KS (REKS) method and its excited state extensions, the state-averaged REKS (SA-REKS) and the state-interaction SA-REKS (SI-SA-REKS, or SSR), − enable fast and accurate computation of the ground and excited state potential energy surfaces (PESs) and conical intersections between them. , As EKT employs the orbital Lagrangian and the relaxed density matrix, the quantities occurring in the SSR analytical energy gradient, , the EKT-SSR method can obtain the molecular IPs during the nonadiabatic molecular dynamics (NAMD) simulations, which enables on-the-fly modeling of the TRPES spectra without computational overhead …”