Kranabetter Lorenz, Kristensen Henrik H, Ghazaryan Areg, Schouder Constant A, Chatterley Adam S, Janssen Paul, Jensen Frank, Zillich Robert E, Lemeshko Mikhail, Stapelfeldt Henrik
Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
Phys Rev Lett. 2023 Aug 4;131(5):053201. doi: 10.1103/PhysRevLett.131.053201.
We demonstrate that a sodium dimer, Na_{2}(1^{3}Σ_{u}^{+}), 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 Schrödinger 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.