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.

GRAPHICAL ABSTRACT

KEYWORDS:

• ¹²C¹⁶O
• photodissociation
• vacuum ultraviolet
• branching ratio

Acknowledgements

This work is supported by the National Natural Science Foundation of China (grant number 21803072), the Program for Young Outstanding Scientists of Institute of Chemistry, Chinese Academy of Science (ICCAS), and Beijing National Laboratory for Molecular Sciences (BNLMS). We also thank Prof. Yang Pan (National Synchrotron Laboratory, University of Science and Technology of China) for the instrumentation supports.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Hong Gao http://orcid.org/0000-0002-6168-7630

Additional information

Funding

This work is supported by the National Natural Science Foundation of China (grant number 21803072), the Program for Young Outstanding Scientists of Institute of Chemistry, Chinese Academy of Science (ICCAS), and Beijing National Laboratory for Molecular Sciences (BNLMS).