Berlin 2014 – scientific programme

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MO: Fachverband Molekülphysik

MO 1: Cold Molecules 1

MO 1.2: Talk

Monday, March 17, 2014, 11:00–11:15, BEBEL HS213

Superfluid Helium Solvation Effects on Hydrogen Bonded Molecules — •Łukasz Walewski, Harald Forbert, and Dominik Marx — Ruhr-Universität Bochum, Bochum, Deutschland

Atomic nuclei become delocalized at low temperatures as a result of quantum effects. For non-interacting atoms the magnitude of this effect increases upon lowering the temperature according to the thermal de Broglie wavelength of free particles. However, strong interactions due to chemical bonding that set in for atoms bound in molecules, counteract this tendency resulting in the, so called, “interaction induced localization”. This effect turns out to be extremely pronounced at ultra-low temperatures of about 1 K, characteristic to superfluid helium nanodroplets. The most affected are protons shared in hydrogen bonds [1], which are confined to a spatial region that corresponds to about 0.1% of the volume occupied by a non-interacting proton at the same temperature. Moreover, applying our recently developed hybrid ab initio MD / bosonic MC path integral method [2] to an HCl/water cluster, HCl(H₂O)₄, we find that helium solvation has a significant additional localizing effect. In particular, the solvent-induced excess localization is the stronger the lesser the given nucleus is already localized in the gas phase reference situation [3].

[1] Walewski, Ł.; Forbert, H.; Marx, D. Mol. Phys., 2013, 111, 2555.
[2] Walewski, Ł.; Forbert, H.; Marx, D. Comp. Phys. Comm. (accepted).
[3] Walewski, Ł.; Forbert, H.; Marx, D. J. Chem. Phys. (submitted).