We investigate how optimal control theory can be used to improve Circular Dichroism (CD) signals for A--band of fenchone measured via the photoionization yield upon further excitation. These transitions are electric dipole forbidden to first order, which translates into low population transfer to the excited state (~8%) but also allows for a clearer interplay between electric and magnetic transition dipole moments, which are of the same order of magnitude. Using a model including the electronic ground and excited A state as well as all permanent and transition multipole moments up to the electric quadrupole, we find that the absolute CD signal of randomly oriented molecules can be increased by a factor 3.5 when using shaped laser pulses, with the anisotropy parameter g increasing from 0.06 to 1. Our insights provide additional evidence on how optimal control can assist in amplifying chiral signatures via interactions of permanent and transition multipole moments.
@article{arxiv.2202.12235,
title = {Increasing ion yield circular dichroism in femtosecond photoionisation using optimal control theory},
author = {Manel Mondelo-Martell and Daniel Basilewitsch and Hendrike Braun and Christiane P. Koch and Daniel M. Reich},
journal= {arXiv preprint arXiv:2202.12235},
year = {2022}
}