We demonstrate that a sodium dimer, Na2(13Σu+), residing on the surface of a helium nanodroplet, can be set into rotation by a nonresonant 1.0 ps infrared laser pulse. The time-dependent degree of alignment measured, exhibits a periodic, gradually decreasing structure that deviates qualitatively from that expected for gas phase dimers. Comparison to alignment dynamics calculated from the time-dependent rotational Schr\"{o}dinger equation shows that the deviation is due to the alignment dependent interaction between the dimer and the droplet surface. This interaction confines the dimer to the tangential plane of the droplet surface at the point where it resides and is the reason that the observed alignment dynamics is also well-described by a 2D quantum rotor model.
@article{arxiv.2308.15247,
title = {Nonadiabatic Laser-Induced Alignment Dynamics of Molecules on a Surface},
author = {Lorenz Kranabetter and Henrik H. Kristensen and Areg Ghazaryan and Constant A. Schouder and Adam S. Chatterley and Paul Janssen and Frank Jensen and Robert E. Zillich and Mikhail Lemeshko and Henrik Stapelfeldt},
journal= {arXiv preprint arXiv:2308.15247},
year = {2023}
}