ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
High resolution (0.0003 cm−1) time-resolved diode laser absorption spectroscopy has been used to reinvestigate the electronic–vibrational energy transfer from spin–orbit excited bromine, Br(2P1/2), to carbon dioxide. The experiments are carried out by generating Br* atoms with pulsed 193 nm laser photolysis of CF3Br and monitoring the subsequent energy transfer by following directly the temporal evolution of selected vibrational states of CO2 (1001, 0201, 0221 and 0001). By comparing the temporal profile of the 1001 state with that predicted by various kinetic models it has been established that quenching of Br* by CO2 occurs via the nearly resonant 1001 state. The E–V rate measured in the present study, (4.8±0.6)×105 Torr−1 s−1, agrees well with that reported previously using infrared fluorescence probes. It has also been determined that the efficiency of this energy transfer is 0.87±0.15; that is, on average, 87% of the spin–orbit excited energy of the Br* atoms will show up as CO2 vibrational energy. The rate constant for the vibrational relaxation of the 1001 state is found to be (4.1±0.5)×106 Torr−1 s−1, also in good agreement with previous low resolution fluorescence measurements.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.458866
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