Coherent control using kinetic energy and the geometric phase of a conical intersection

TL;DR

This paper introduces two novel methods for controlling molecular dynamics near conical intersections using light fields, enabling manipulation of electronic states and wavepackets, which advances understanding of nuclear-electronic coherence effects.

Contribution

It presents new control techniques exploiting kinetic energy and geometric phase at conical intersections, expanding the toolkit for molecular quantum control.

Findings

Controlled population transfer using continuous light fields.

Wavepacket manipulation via pulsed light and geometric phase.

Potential applications in studying nuclear-electronic coherence.

Abstract

Conical intersections (CI) between molecular potential energy surfaces with non-vanishing non-adiabatic couplings generally occur in any molecule consisting of at least three atoms. They play a fundamental role in describing the molecular dynamics beyond the Born-Oppenheimer approximation and have been used to understand a large variety of effects, from photofragmentation and isomerization to more exotic applications such as exciton fission in semiconductors. However, few studies have used the features of a CI as a tool for coherent control. Here we demonstrate two modes of control around a conical intersection. The first uses a continuous light field to control the population on the two intersecting electronic states in the vicinity of a CI. The second uses a pulsed light field to control wavepackets that are subjected to the geometric phase shift in transit around a CI. This second technique is likely to be useful for studying the role of nuclear dynamics in electronic coherence phenomena.