High resolution electronic study of 16O14N16O, 16O14N18O and 18O14N18O:: A rovibronic survey covering 11 800-14 380 cm-1

The 11800-14380 cm(-1) frequency range has been scanned for rotationally resolved rovibronic transitions in the A(2)B(2)-X(2)A(1) electronic band system of the symmetric (C-2 upsilon) (ONO)-O-16-N-14-O-16 and (ONO)-O-18-N-14-O-18 isotopologues and in the corresponding electronic band system of the asymmetric (C-s) (ONO)-O-18-N-14-O-16 isotopologue. The rotational analysis-reflecting minor differences in mass-in combination with symmetry induced spectral differences allows an identification of 68 (ONO)-O-16-N-14-O-16 vibronic levels, 26 (ONO)-O-18-N-14-O-18 vibronic levels and 51 (ONO)-O-18-N-14-O-16 vibronic levels. The bands are recorded using near infrared fluorescence spectroscopy and a piezo valve based pulsed molecular beam expansion of premixed O-18(2) and (NO)-N-14-O-16 in Ar. The majority of the observed bands is rotationally assigned and can be identified as transitions starting from the vibrational ground state of one of the isotopologues. Numerous hot bands have also been identified. A comparison of the overall spectroscopic features of C-2 upsilon vs. C-s symmetric species provides qualitative information on symmetry dependence of vibronic couplings. (C) 2006 Elsevier Inc. All rights reserved.