Structure and conformational dynamics of the cyclopropyl methyl ketone molecule in the ground electronic state

Geometric parameters, vibrational frequencies, conformer energy difference, and barriers to internal rotation for the cyclopropyl methyl ketone (CPMK, c-С3H5C(O)CH3) molecule in the ground electronic state were obtained by performing MP2, MP4(SDQ), CCSD, and CCSD(T) calculations and VFPA. Ab initio one-dimensional and two-dimensional potential functions corresponding to the rotations of the acetyl C(O)CH3 and methyl CH3 tops were used to calculate torsion transition energies by the variational method. Two torsion motions were found to be strongly coupled in the region of the near-trans conformer of CPMK.