(N2O)-N-14-O-16 in emission in the 4.5-mu m region: Transitions v(1)v(2)(vertical bar)v(3) -> v(1)v(2)(vertical bar)(v(3)-1) occurring between highlyexcited vibrational states

The experimental technique which consists of exciting a mixture of N2O and N-2 by radio frequency is very efficient for populating very high vibration al levels. Twelve emission spectra of mixtures of N2O and N-2 were recorded with a Fourier transform spectrometer at resolutions of 0.006,0.004, and 0 .003 cm(-1) in the 4.5-mum region. Among the already known transitions, 10 new vibrational transitions which occur between highly excited levels have been observed. In particular, we have detected the very weak transitions 00 (0)5 --> 00(0)4 and 04(0)4 --> 04(0)3, which involve the interacting levels 0005 and 04(0)4. The wavenumbers are reported as well as the derived spect roscopic parameters, which allow one to reproduce the experimental wavenumb ers within experimental accuracy (< 4 x 10(-4) cm(-1)). The results are in good agreement with the new predictions of N2O line positions which have be en made using a model calculation based upon the effective hamiltonian appr oach. (C) 2001 Academic Press.