MP2/6-31G-ASTERISK/MP2/6-31G-ASTERISK VIBRATIONAL ASSIGNMENTS OF THE S-TRANS AND S-CIS ROTAMERS OF 2-FLUOROPROPENOYL FLUORIDE, CH2=CF-CF=O

Complete MP2/6-31G(*) geometry optimizations and MP2/6-31G(*)//MP2/6-31G(*) force field computations for the s-trans- and s-cis-2-fluoropropenoyl fluoride conformers are reported. Both rotamers are predicted to be entirely planar and to be at energy minima on the torsional potential curve for rotation around the formal single C-C bond. In agreement with experiment, the s-trans structure is predicted to be lowest in energy. For both conformers the theoretical fundamental vibrational frequencies are calculated using the unsealed and scaled MP2/6-31G(*)//MP2/6-31G(*) force fields. The IR intensities are calculated using the unsealed MP2/6-31G(*)//MP2/6-31G(*) force fields. All the fundamental vibrational frequencies of the s-trans- and s-cis-2-fluoropropenoyl fluoride rotamers are assigned. Compared to a recent vibrational analysis, the attributions of nine fundamental frequencies for each of the s-trans and s-cis rotamers are changed.