Nuclear quantum effects on the nonadiabatic decay mechanism of an excited hydrated electron

Abstract

We present a kinetic analysis of the non-adiabatic decay mechanism of an excited state hydrated electron to the ground state. The theoretical treatment is based on a quantized, gap dependent golden rule rate constant formula which describes the non-adiabatic transition rate between two quantum states. The rate formula is expressed in terms of quantum time correlation functions of the energy gap, and of the non-adiabatic coupling. These gap dependent quantities are evaluated from three different sets of mixed quantum-classical molecular dynamics simulations of a hydrated electron equilibrated a) in its ground state, b) in its first excited state, and c) on a hypothetical mixed potential energy surface which is the average of the ground and the first excited electronic states. The quantized, gap-dependent rate results are applied in a phenomenological kinetic equation which provides the survival probability function of the excited state electron. Although the lifetime of the equilibrated excited state electron is computed to be very short (well under 100 fs), the survival probability function for the non-equilibrium process in pump-probe experiments yields an effective d

Nuclear quantum effects in electronically adiabatic quantum time correlation functions: Application to the absorption spectrum of a hydrated electron

“…We have also found that the non-adiabatic coupling fluctuations are strongly dominated by the librational and vibrational solvent modes. 17,18 We will show in the next section that this is also true for the transition dipole fluctuations. A harmonic bath description (for which the formula is exact) is thus quite sensible, at least for this application.…”

“…We argued previously that the harmonic quantization scheme was fully justified for quantizing the solvated electron nonadiabatic transition rates. 17,18 We have shown 17 that, for the energy gap fluctuations, this scheme leads to the correct decoherence times for an excited p-electron when compared to the Gaussian packet propagation approach of Prezhdo and Rossky, 38 and Turi and Rossky, 39 both for water and methanol. This argument is still valid for the present application.…”

“…Our approach is inspired by a previous work where we derived a quantum time correlation formula for the nonadiabatic decay rate between two adiabatic quantum electronic states coupled to a nuclear bath starting from the Fermi golden rule. 17,18 The quantum time correlation of the nonadiabatic coupling operator, involving both electronic and nuclear degrees of freedom, was expressed in terms of the nuclear quantum time correlation functions of the state-to-state nonadiabatic (kinetic energy)…”

Cosmic-ray-driven electron-induced reactions of halogenated molecules adsorbed on ice surfaces: Implications for atmospheric ozone depletion and global climate change

“…Prior to 2008, many experimental and theoretical studies gave very diverse lifetimes and physical natures of e pre states in liquid water [49][50][51][52][53][54][58][59][60][61][62]. But Wang et al [28] have recently resolved that e pre states are electronically excited states and have lifetimes of ~200 and 500 fs after the identification and removal of a coherent spike effect.…”

“…In 2000s, Researches on electron solvation dynamics and associated dissociative electron transfer reactions of halogenated molecules have continued in water solution [21,[27][28][29][58][59][60][61][62], ice surface [63], ultrathin ice films [16,17,[64][65][66][67] and H 2 O anionic clusters [68][69][70][71][72][73]. Prior to 2008, many experimental and theoretical studies gave very diverse lifetimes and physical natures of e pre states in liquid water [49][50][51][52][53][54][58][59][60][61][62].…”