Excitation transfer from Kr(5s′,3P) and Kr(5s,3P2) atoms to 12CO and 13CO

Emission spectra have been used to characterize the excitation-transfer reactions from Kr(5s′,3P0) and Kr(5s,3P2) metastable atoms to 12CO and 13CO at 300 K. The most important products from the Kr(3P0) reactions are 12CO and 13CO(b 3Σ+,v′=0 and 1) and 12CO(a′ 3Σ+,v′=34 and 35) and 13CO(a′ 3Σ+,v′=35 and 36). The rotational distributions of the CO(a′ 3Σ+) and CO(b 3Σ+,v′=1) levels are cold, but the CO(b 3Σ+,v′=0) distribution is rotationally excited. The populations in the 12CO(a′,v′=34 and 35) levels are transferred to CO(b,v′=0) by collisions with He and the rate constants are 0.4–1.0×10−10 cm3 s−1. Emission spectra from the Kr(3P2) reaction identified 12CO(a′,v′=23–26) and 13CO(a′,v′=24–27) and CO(d 3Δ,v′=20 and 21) for both 12CO and 13CO as important products; the CO(d 3Δ,v′=20 and 21) states previously were identified by Tsuji and co-workers. The vacuum ultraviolet spectra from the Kr(3P2) reaction with 12CO and 13CO showed that CO(A 1Π) is a primary product and that it also is formed from CO(d 3Δ) and CO(a′ 3Σ+) by collisions with He and Ar. The Kr(3P2)+CO reaction also generates some unassigned CO triplet state emission. The propensity for formation of 3Σ+ states rather than the e 3Σ− state of CO is discussed. An improved transition dipole function for the CO(b 3Σ+–a 3Π) transition is presented in the Appendix.