Model two states dynamics of photo-detachment [F-H-F] − $$ {}^{-} $$ induced by an optimally designed polychromatic field

Abstract

Photo-detachment of electron from [F-H-F]${}^{-}$ to generate neutral [F-H-F] has been studied in this article. Neutral ${\text{HF}}_2$ has a linear structure and this is the transition state (T.S.) of F + HF $\to$ FH + F reaction. The Potential Energy Surface (P.E.S.) of neutral [F-H-F] and molecular anion [F-H-F]${}^{-}$ for the asymmetric stretching mode is generated and the dynamics under the influence of an external polychromatic field is followed. The P.E.S. of [F-H-F]${}^{-}$ looks like a “flat-bed” single well where as for [F-H-F] it has a symmetrical double well structure. In absence of any external field these two surfaces are well separated. But in presence of external field transition from molecular anion $($[F-H-F]${}^{-}$ $)$ to neutral molecule $($[F-H-F]$)$ takes place which causes the detachment of an electron. We have designed an optimal designed field using Simulated Annealing and studied the dynamics of electron detachment by such external fields. We have achieved detachment probability of $90\%$ by applying the optically designed field.