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MO: Molekülphysik
MO 55: Poster: Collisions and Energy Transfer
MO 55.3: Poster
Thursday, March 16, 2006, 16:30–18:30, Labsaal
Collision-induced rototranslational absorption in compressed methane gas — •Michael Buser1 and Lothar Frommhold2 — 1Universität Ulm — 2University of Texas at Austin
Transient collisional complexes of two or more atoms or molecules acquire properties which do not exist in the non-interacting constituents. Collision-induced, rototranslational absorption spectra in even non-polar molecules arise. Such spectra were calculated for methane molecules numerically, based on a theoretical dipole function which accounts for the long-range induction mechanisms: multipolar induction and induction by dispersion and exchange forces. By comparing the computed results to existing measurements, a sizeable absorption defect at virtually all frequencies can be observed. The occurence in different methane gas mixtures like CH4–N2, CH4–H2, CH4–He and CH4–CH4 considered in this work suggests the presence of an addition induction mechanism, which seems to be related to collisional distortion of the tetrahedral frame of the unperturbed CH4 molecule.