The NO dimer .1. Analysis of the nu(5) band

The antisymmetric vibration nu(5) of the NO dimer was studied by high resolution infrared Fourier transform spectroscopy. The dimer was produced at thermodynamical equilibrium, in the temperature range 127-154 K, in a White-type multipass cell for NO pressures ranging from 26 to 88 mbar. The upper level spectroscopic constants A', B', and C' of the dimer could be measured from the spectra. An estimate of the lifetime of the excited state was made possible from the measurement of the anomalously large linewidths. The binding energy D-0 was also derived from the intensities of the three branches of the A-type transition recorded at various temperatures; the obtained value of D-0 is in good agreement with results reported in previous studies. (C) 1997 Academic Press.