Free jet IR spectroscopy of (32SF6)2 in the 10 μm region

The rotation-vibration spectra of (32SF6)2 have been studied near the ν3 band of the 32SF6 monomer. The parallel band 14 cm−1 below the monomer band origin shows a well resolved J-structure, while the perpendicular band 8 cm−1 above the origin exhibits several Q-branch peaks as the only resolved strong lines. The structure of (32SF6)2 is consistent with a D2d symmetry from the intensity alternation and the existence of a first-order Coriolis interaction observed in the perpendicular band. The energy difference between the two bands is very close to the value calculated by a dipole–dipole and dipole-induced dipole interaction model, while the location of the two bands is blueshifted from the calculated values by about 2 cm−1. The possible influence of internal rotation is discussed.