Br*+CO sub 2 revisited: An interrogation of E -- V energy transfer with time-resolved diode laser spectroscopy
- Brookhaven National Laboratory, Department of Chemistry, Upton, NY (USA)
- Department of Chemistry, Columbia University, New York, NY (USA) Columbia Radiation Laboratory, Columbia University, New York, NY (USA)
High resolution (0.0003 cm{sup {minus}1}) time-resolved diode laser absorption spectroscopy has been used to reinvestigate the electronic--vibrational energy transfer from spin--orbit excited bromine, Br({sup 2}{ital P}{sub 1/2}), to carbon dioxide. The experiments are carried out by generating Br* atoms with pulsed 193 nm laser photolysis of CF{sub 3}Br and monitoring the subsequent energy transfer by following directly the temporal evolution of selected vibrational states of CO{sub 2} (10{sup 0}1, 02{sup 0}1, 02{sup 2}1 and 00{sup 0}1). By comparing the temporal profile of the 10{sup 0}1 state with that predicted by various kinetic models it has been established that quenching of Br* by CO{sub 2} occurs via the nearly resonant 10{sup 0}1 state. The {ital E}--{ital V} rate measured in the present study, (4.8{plus minus}0.6){times}10{sup 5} Torr{sup {minus}1} s{sup {minus}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{plus minus}0.15; that is, on average, 87% of the spin--orbit excited energy of the Br* atoms will show up as CO{sub 2} vibrational energy. The rate constant for the vibrational relaxation of the 10{sup 0}1 state is found to be (4.1{plus minus}0.5){times}10{sup 6} Torr{sup {minus}1} s{sup {minus}1}, also in good agreement with previous low resolution fluorescence measurements.
- DOE Contract Number:
- FG02-88ER13937
- OSTI ID:
- 6546201
- Journal Information:
- Journal of Chemical Physics; (USA), Vol. 93:4; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOM-MOLECULE COLLISIONS
ENERGY TRANSFER
BROMINE
CARBON DIOXIDE
ABSORPTION SPECTROSCOPY
EXCITED STATES
KINETICS
LASER SPECTROSCOPY
RELAXATION
TIME RESOLUTION
VIBRATIONAL STATES
ATOM COLLISIONS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
ELEMENTS
ENERGY LEVELS
HALOGENS
MOLECULE COLLISIONS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RESOLUTION
SPECTROSCOPY
TIMING PROPERTIES
400201* - Chemical & Physicochemical Properties