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Quantum-classical dynamics of the capture of neon atoms by superfluid helium nanodroplets

M. Blancafort-Jorquera, A. Vila, M. González.
Phys. Chem. Chem. Phys., 20 (2018) 29737.

Quantized vortex in the top left part of the helium density (left) and phase of the helium wave function (right), for the most probable velocity of Ne at 300 K (v0=500 m s-1), impact parameter b=17 Å and final simulation time (171.2 ps).

The capture of a Ne atom by a superfluid helium nanodroplet, Ne + (4He)N → Ne@(4He)N’ + (N-N’) 4He, was studied using a hybrid quantum (helium)-classical (Ne) approach, taking into account for the first time the angular momentum (and the resulting vortex formation) in a detailed way. Large energy and angular momentum transfer from the atom to the nanodroplet occur and the angular momentum of the Ne atom can induce vortex nucleation for high enough initial angular momentum values (~176.3-220.3 !). Vortices arise from collapse of the surface excitations (ripplons) and are long-lived for some initial conditions. Comparison with a previous quantum dynamics study of our own at zero angular momentum shows that quantum effects are not important under the initial conditions examined here. Besides, a comparison with the scarce information available on other systems has been performed, showing the rich variety of behaviours that can be observed in the solvation of impurities by superfluid helium.