Mainz 2017 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 7: Helium Droplets and Systems (with A)

MO 7.2: Vortrag

Dienstag, 7. März 2017, 15:00–15:15, N 6

Libration of strongly-oriented polar molecules inside a superfluid — •Elena Redchenko and Mikhail Lemeshko — IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria

Recently, it was shown that molecular rotation inside a superfluid, such as a helium nanodroplet or a Bose-Einstein condensate, leads to formation of a quasiparticle of a new kind -- the angulon. The angulon represents a quantum rotor dressed by a field of many-particle excitations. In this work, we demonstrate that in the strong-field limit the angulon turns into the 'pendulon' -- a quantum spherical librator, whose pendular motion is altered by the field of phonon excitations, and study the properties of the pendulon quasiparticle. We have shown that an electric field relaxes the selection rules on the angular momentum exchange between the molecule and the bath, which results in a series of instabilities absent in the field-free case of the angulon quasiparticle. In other words, a field renders the instabilities universal, i.e. independent on the details of the molecule-boson potential energy surface. Furthermore, a field acts as an additional knob for altering the positions of the instabilities in the molecular rotational spectrum, thereby opening the door for detailed experimental studies of redistribution of orbital angular momentum in many-particle systems.

[1] Redchenko E.S., Lemeshko M., Chemphyschem. 2016 Nov 18;17(22):3649-3654.