PRESSURE BROADENING AND PRESSURE SHIFT COEFFICIENTS IN THE 2V(2)(0) AND V(1) BANDS OF (OCO)-O-16-C-13-O-18

In this study we report the first measurements of the pressure broaden ing and the pressure-induced line shift coefficients due to air and ni trogen for 93 individual rovibrational lines, P(46) to R(46) and P(50) to R(45), respectively, belonging to the 2 nu(2)(0) and nu(1) bands o f (OCO)-O-16-C-13-O-18. The results were obtained by analyzing ten lon g path, high-resolution laboratory absorption spectra using a multispe ctrum nonlinear least-squares technique. Broadening due to nitrogen wa s about 4% larger than by air. Similar to broadening coefficients, the pressure-shift coefficients were found to be transition dependent, bu t different for the P- and R-branch lines with the same rotational qua ntum number, J. Except for a few R-branch lines, the measured shift co efficients were negative. The shift coefficients varied from +4 x 10(- 3) cm(-1)atm(-1) at 296 K to - 5.6 x 10(-3) cm(-1)atm(-1) at 296 K. Co mparisons of the broadening and shift coefficients between the two ban ds, between the P and R branches, and between the two broadening gases are reported. No significant difference between shift coefficients of the two bands or the two broadening gases was observed. The results o btained were compared with those reported in the literature for the mo re abundant (CO2)-C-12-O-16 species. (C) 1998 Elsevier Science Ltd. Al l rights reserved.