Photodissociation branching ratios for several absorption bands of 12C16O from 108,500 to 109,220 cm−1

Abstract

In the present study, photodissociation branching ratios are measured with optimised experimental conditions for the 12C16O absorption bands with upper states of I′(5sσ) 1Σ+(v′ = 1), (6sσ) 1Σ+(v′ = 0) and (6pπ) 1Π(v′ = 0), which were not observed in the recent study covering the titled energy range (J. Chem. Phys. 137, 034305 (2012)). The absorption band with the upper state of (6pσ) 1Σ+(v′ = 0) has been reinvestigated, and a weak dependence of branching ratios into the spin-forbidden channels on the rotational quantum number is observed. In addition to these relatively strong absorption bands, two weak bands have also been identified in the C+ ion photofragment spectra, one with well rotationally resolved 1Π character and has never been observed before, and the other with diffuse structure and its upper state was assigned as C′1Σ+(v′ = 9) before in spectroscopic studies. Except for the two newly observed weak absorption bands, the four strong absorption bands all predominantly dissociate into the ground channel C(3P)+O(3P). By far, we have finished measuring the photodissociation branching ratios for all the strong 12C16O absorption bands of astrophysical importance above the photon energy of 102,700 cm−1.