INTENSITY MEASUREMENTS OF DELTA-L-GREATER-THAN-1 TRANSITIONS OF SEVERAL ISOTOPOMERS OF HCN

The intensities of the forbidden Q-branch transitions 02(2f)0-00(0)0, 12(2f)0-00(0)0, and 02(2f)1-00(0)0 for HCN have been measured. The int ensities of the 0(2f)0-00(0)0 transitions of DCN, (DCN)-C-13-N-15, and (HCN)-C-12-N-15 were also measured, as well as the 0(2f)1-00(0)0 tran sitions of (HCN)-C-12-N-15 and (HCN)-C-13-N-15. These Q-branch transit ions are forbidden even when the effects of l-type resonance are consi dered so they must get their intensity from some other Coriolis intera ctions, The much stronger P-and R-branch lines for the e levels of the se same vibrational transitions were also measured and they are shown to get most of their intensity from l-type resonance. However, the sam e Coriolis resonance that gives intensity to the Q-branch transitions seems to affect the Delta J = +/-1 transitions as shown by the differe nce in the intensities of the Delta J = +1 and Delta J = -1 transition s. Measurements of the intensity of the 03(3e)0-00(0)0 and 03(3f)0-00( 0)0 transitions shows that they derive most, but perhaps not all, of t heir intensity from I-type resonance. An unsuccessful search for forbi dden Delta J = 0, e-e transitions for the strong 10(0)0-00(0)0 band sh ows that there is no detectable mixing of the e and f levels. (C) 1997 Academic Press.