Multilevel vibrational-vibrational (V-V) energy transfer from CO(v) to O-2and CO2

The vibrational-vibrational (V-V) energy transfer from excited CO(upsilon l ess than or equal to 10) to O-2 and CO2 molecules was studied by laser-indu ced chemiluminscence/time-resolved Fourier transform infrared emission spec troscopy. The vibrationally excited CO molecules were produced by 193 nm ph otolysis of a mixture of CHBr3 and O-2 The temporal populations of the 10 v ibrational states of CO were obtained from the time-resolved IR emission sp ectra. The rate equations were solved by a differential method we have sugg ested. Nine vibrational quenching rate constants k(upsilon) (upsilon = 1-9) of O-2 were found to be 1.1 +/- 0.1, 1.9 +/- 0.1, 2.0 +/- 0.2, 2.3 +/- 0.3 , 2.5 +/- 0.3, 3.0 +/- 0.3, 4.0 +/- 0.5, 4.8 +/- 0.5, and 8.0 +/- 0.8 (x 10 (-14) cm(3) molecule(-1) s(-1)). And the k(upsilon) (upsilon = 1-8) quenche d by CO2 were 5.7 +/- 0.1, 5.9 +/- 0.1, 5.3 +/- 0.2, 3.4 +/- 0.3, 2.4 +/- 0 .3, 2.2 +/- 0.2, 2.0 +/- 0.2, and 1.8 +/- 0.2 (x 10(-14) cm(3) molecule(-1) s(-1)), respectively. The trend of the (k(upsilon)) with upsilon for CO/O- 2 system was explained by a V-V energy transfer mechanism of single channel . For the CO/CO2 system, a multichannel model, transferring the energy to t he nu(1), nu(3) and several overtone vibrational modes of CO2 molecule, was suggested. A modified SSH theoretical calculation fits well to the experim ental data.