The ν1 and ν2 bands of Ar•••HN2+:: A joint theoretical/experimental study

A combined theoretical and experimental study of the nu(1) and nu(2) stretching vibrations of Ar ... HN2+ is presented. These correlate asymptotically with the almost local NH and NN stretching vibrations of free HN2+, but undergo mode mixing and are strongly influenced by vibrational anharmonicity in the complex. The first observation of the strong nu(2) band by means of diode laser absorption spectroscopy in a supersonic planar plasma is reported. Its band origin is found at 2041.1802(3) cm(-1). New results are presented for the nu(1) band with origin at 2505.5000(2) cm(-1). The ground-state rotational constant is determined from both band systems as 0.080 868(6) cm(-1). (C) 2000 American Institute of Physics. [S0021-9606(00)00729-7].