The nu(1) and nu(2) bands of Ar center dot center dot center dot HN2+: A joint theoretical/experimental study

A combined theoretical and experimental study of the nu(1) and nu(2) stretc hing vibrations of Ar ... HN2+ is presented. These correlate asymptotically with the almost local NH and NN stretching vibrations of free HN2+, but un dergo 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 report ed. Its band origin is found at 2041.1802(3) cm(-1). New results are presen ted 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) c m(-1). (C) 2000 American Institute of Physics. [S0021-9606(00)00729-7].