Regensburg 2010 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 1: Statistical Physics (general) I

DY 1.5: Talk

Monday, March 22, 2010, 11:15–11:30, H47

Quantum–induced symmetry breaking explains infrared spectra of CH₅⁺ isotopologues — •Alexander Witt, Sergei D. Ivanov, and Dominik Marx — Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum, Germany

Protonated methane, CH₅⁺, has been investigated intensively using a host of different experimental and theoretical techniques since decades, see Ref. [1] for a review. The challenge to theory arises from its shallow potential energy surface which leads to dynamical equivalence of the hydrogen atoms often referred to as ”scrambling”. It has been shown that this is driven by quantum fluctuation effects of the nuclei [2].

Ab initio MD in combination with techniques based on Feynman’s formulation of quantum statistical mechanics in terms of path integrals allows us to fully reproduce the experimental IR spectra of all isotopologues of CH₅⁺. Moreover, an analysis technique developed in–house enables full assignment of spectral features to molecular motions.

[1] P. Kumar P. and D. Marx, Phys. Chem. Chem. Phys. 8, 573 (2006)

[2] D. Marx and M. Parrinello, Nature 375, 216 (1995)