Theoretical investigation of the structure and vibrational spectra of diethynyl ketone

The molecular structure, vibrational frequencies and the corresponding vibrational assignments of diethynyl ketone (HC≡C)₂CO in C _s symmetry were examined theoretically using DFT-B3LYP, DFT-BLYP and MP2 with the standard 6-311++G** basis set. The calculated Infrared and Raman spectra of the molecule were plotted. Observed frequencies for normal modes were compared with those calculated from normal mode coordinate analysis carried out on the basis of ab initio and DFT force fields using the standard 6-311++G** basis set of the theoretical optimized geometry. Theoretical IR intensities and Raman activities are reported.