CURRENT ReSEARch

My research is aimed at controlling bond-breaking in triatomic hydrogen-bonded anions, XHY^-. The motivation behind this work is two-fold. First, transition state spectroscopy (see the work of D. Neumark) experiments have been performed to study the transition state of hydrogen-bihalide ions via photoelectron detachment. In these experiments, photodetachment of an electron froma triatomic anion excites the species to a higher-lying potential energy surface (PES), on which the neutral species proceeds to dissociate along two channels, see Scheme 1.

Our project focuses on this dissociation step and raises the question: can we influence the bifurcation process and control the branching ratio of products?

Scheme 1: Equal branching ratio of products XH+Y and X+HY

This question is also dealt with in theoretical studies (see the work of N.E. Henriksen) that have examined the bond-selective fragmentation of triatomic systems using ultrashort infrared (IR) laser pulses. Such IR pulses are on the timescale of one vibrational period (<50 fs) and are capable of preparing a wavepacket in the ground state that consists of a superposition of vibrational eigenstates. Excitation of such wavepackets via a subsequent ultrashort UV pulse to a dissociative PES can lead to the bond-selective dissociation of the excited species, see Scheme 2. Our challenge is, therefore, to control the bond-selective dissociation in hydrogen-bonded ions using ultrashort IR and UV laser pulses.

Scheme 2: Bond selective dissociation