A moderately intense 450 fs laser pulse is used to create rotational wave packets in gas phase I2 molecules. The ensuing time-dependent alignment, measured by Coulomb explosion imaging with a delayed probe pulse, exhibits the characteristic revival structures expected for rotational wave packets but also a complex non-periodic substructure and decreasing mean alignment not observed before. A quantum mechanical model attributes the phenomena to coupling between the rotational angular momenta and the nuclear spins through the electric quadrupole interaction. The calculated alignment trace agrees very well with the experimental results.
@article{arxiv.1804.04416,
title = {Hyperfine-Structure-Induced Depolarization of Impulsively Aligned $\rm I_2$ Molecules},
author = {Esben F. Thomas and Anders A. Søndergaard and Benjamin Shepperson and Niels E. Henriksen and Henrik Stapelfeldt},
journal= {arXiv preprint arXiv:1804.04416},
year = {2018}
}
Comments
6 pages, 4 figures, and Supplementary Information. This article has been accepted for publication in Physical Review Letters