Vibrational frequencies and structural determination of tetraiododiphosphine

The normal mode frequencies and corresponding vibrational assignments of of tetraiododiphosphine in C2h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of six types of motion (P-I stretch, P-P stretch, PI2 scissors, PI2 twist, PI2 wag, and PI2 rock) predicted by a group theoretical analysis. Computed vibrational frequencies are with IR and Raman spectra available in the literature, and uniform scaling factors are derived. Theoretical IR and Raman intensities are reported.