Infrared diode laser spectroscopy of the 5g–4f Rydberg transition of nitric oxide

Abstract

The 5g – 4f Rydberg transition of nitric oxide has been recorded by high-resolution diode laser absorption spectroscopy. The excited states were generated in a low-pressure ac discharge and studied with population modulation detection. The spectra have been assigned and analysed using the multipole-polarization, or long-range interaction model, and the theoretical background is given, including terms up to <r−5>. Values of the quadrupole moment and polarizability terms of the NO+ (X1Σ+) ion core, as well as a core penetration factor, have been determined in a least-squares fitting procedure. Experimental values for the core properties are compared with recent ab initio calculations.