Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

Poster session, J36 199Theoretical analysis of the proton tunneling and internal rotationin 2-methylmalonaldehydeIwona Gulaczyk, Marek KręglewskiAdam Mickiewicz University, Poznań, gulai@amu.edu.pl, PolandGulaczyk I.Kreglewski M.The 2-methylmalonaldehyde (2-MMA) is an interesting example of a moleculeexhibiting two large amplitude motions – a proton tunneling and an internal rotation ofthe methyl top. Both motions are coupled mutually and with the total rearrangement ofthe molecular skeleton. The proton tunneling forces the exchange of single and doublebonds of the skeleton and, consequently, the rotation of the methyl top by 60 degrees.Whereas the proton tunneling of a malonaldehyde has been widely studied, much lesseffort was given to the 2-MMA. In the present work an ab initio two-dimensionalpotential energy surface (PES) is calculated theoretically on the CCSD(T) levelallowing the relaxation of the molecular structure. From the PES the proton tunneling –internal rotation vibrational energy levels are calculated by the semi rigid method. Thetunneling splittings are compared with the experimental data of Ilyushin et al 1 .References[1] V.V.Ilyushin, E.A. Cloessner, Y-C. Chou, L.B. Picraux, J.T. Hougen, R. Lavrich,J.Chem.Phys. 133, 184307, 2010