The effect of coupled nonreactive modes on laser control of quantum wave packet dynamics

Abstract

The laser control of reactions in solution has recently been a topic of growing interest. The theoretical possibility for such control has now been established. This paper investigates two closely related issues regarding potential practical implementation of condensed phase control schemes. A previous study from our group was able to demonstrate control assuming that a laser field coupled only to a reaction coordinate. The assumption that the laser will not couple to the condensed phase environment is a drastic simplification, and we investigate in this paper how relaxing this simplification may affect the possibility of control. To investigate this phenomenon, we study two cases: that of a laser coupled only to a reaction coordinate which is in turn coupled to a “bath” mode, as compared to the case in which the laser is coupled both to the reaction coordinate and the environmental mode. In another closely related investigation, we study the effect of uncertainty introduced into the controlling pulse. The exact potential of a chemical reaction in solution cannot be known to perfect accuracy. Our results give insights into the challenges which will face attempts at condensed phase chemical reaction control, and point strongly to the need for adaptive algorithms for laser control pulse generation.