Active control of decoherence of excited resonance states by means of laser pulses

Abstract

This work explores how to exploit the mechanism of quantum interference occurring between overlapping zero-order resonances within a system [1-3] in order to change and control the lifetime of a specific excited resonance. The system chosen is the Br2(B,v’)-Ne van der Waals (vdW) cluster, since there has been previously shown [4-6] that it presents a range of initial v’ vibrational manifolds for which the ground vdW resonance overlaps with other resonances near in energy corresponding to the v’-1 vibrational manifold. Thus, modification and control of the predissociation lifetime of the ground vdW resonance of Br2(B,v’)-Ne is investigated through wave packet simulations by changing the width of the pulse that creates a coherent superposition of v’ and v’-1 overlapping resonances. Specifically, three different vibrational states v’ are studied corresponding to the isolated (nonoverlapping) resonance regime (v’=16), the sparse overlapping resonance regime (v’=27), and the dense overlapping resonance regime (v’=35). The effect of changing the excitation energy (i.e., the center of the wave packet prepared) along the excitation spectrum of the v’ ground resonance excited is also explored as an additional control parameter.