Infrared Laser Driven Double Proton Transfer. An Optimal Control Theory Study

TL;DR

This study uses optimal control theory and wave packet propagation to investigate laser-driven double proton transfer, highlighting the dominance of stepwise pathways and the conditions under which concerted tunneling occurs.

Contribution

It introduces a combined optimal control and wave packet approach to analyze ultrafast double proton transfer mechanisms in a two-dimensional model.

Findings

Stepwise transfer dominates in all cases.

Concerted tunneling contributes in high barrier systems.

Laser pulse sequences are optimized for controlling transfer pathways.

Abstract

Laser control of ultrafast double proton transfer is investigated for a two-dimensional model system describing stepwise and concerted transfer pathways. The pulse design has been done by employing optimal control theory in combination with the multiconfiguration time-dependent Hartree wave packet propagation. The obtained laser fields correspond to multiple pump-dump pulse sequences. Special emphasis is paid to the relative importance of stepwise and concerted transfer pathways for the driven wave packet and its dependence on the parameters of the model Hamiltonian as well as on the propagation time. While stepwise transfer is dominating in all cases considered, for high barrier systems concerted transfer proceeding via tunneling can make a contribution.