Infrared spectra of the CO2⋅⋅⋅HF and N2O⋅⋅⋅HF complexes in solid argon at 12 K

Abstract

Codeposition of argon diluted samples of CO₂ and HF at 12 K produced new absorptions at 3871, 2354, 656, and 313 cm⁻¹ which are assigned to the CO₂⋅⋅⋅HF complex. The 3871 and 313 cm⁻¹ absorptions are due to the H–F stretching and librational motions of the HF submolecule in the complex, as verified by DF substitution, and the 2354 and 656 cm⁻¹ bands are due to CO₂ submolecule modes. The N₂O⋅⋅⋅HF complex spectrum contained bands at 3851, 2250, 1306, 583, 328, and 325 cm⁻¹. The greater observed displacement in the HF submolecule modes suggests slightly stronger hydrogen bonding in the N₂O complex. The lack of splitting in the degenerate librational mode for CO₂⋅⋅⋅HF shows that this complex is linear, whereas the 3 cm⁻¹ splitting in this mode for N₂O⋅⋅⋅HF is consistent with a nonlinear complex, in agreement with microwave spectra.