Intermolecular potential for Ar-HBr (ν1 = 1) studied by high resolution near infrared spectroscopy

The fundamental ν1, combinations ν1 + 2ν20, ν1 + ν21, ν1 + ν3, ν1 + 2ν20 + ν3, hot band ν1 + 2ν20 − 2ν20, and difference band ν1 − 2ν20 have been rovibrationally for both 79Br and 81Br isotopomers in Ar-HBr. The bands involving 2ν20 directly sample the second minimum of the intermolecular potential surface of the complex, corresponding to the isomeric structure Ar-BrH. Nuclear quadrupole structure has also been partially resolved in the Q branch transitions of the ν1 + ν21 band. In addition, a strong Coriolis perturbation between the ν1 + ν21e and ν1 + ν3 states was investigated. A model potential surface for Ar-HBr (HBr ν1 = 1) was derived and compared with the H4 intermolecular potential for Ar-HBr (HBr ν1 = 0).