Theoretical analysis of the proton transfer and internal rotation in 2-methylmalonaldehyde

For the first time ab initio calculations of the two dimensional potential energy surface (PES) and relaxation of geometrical parameters have been carried out for 2-methylmalonaldehyde (2-MMA) at the of MP2/6-311++G∗∗ level using a Gaussian package. The comparison of calculated energies for two selected configurations shows no significant difference between these results and those at the CCSD(T)/6-311++G∗∗ level. The semi rigid model for the proton transfer and torsion has been applied to d0 and d1 isotopologues of 2-MMA. The ab initio PES was modified using the experimental data from the ground vibrational state. The barriers for the proton transfer and the barriers for internal rotation were obtained.