Diode laser probing of the high-frequency vibrational modes of baths of CO sub 2 , N sub 2 O, and CO excited by relaxation of highly excited NO sub 2
- Department of Chemistry and Columbia Radiation Laboratory, Columbia University, New York, New York 10027 (US)
Quenching of highly excited vibrational states of NO{sub 2} in baths of CO{sub 2}, N{sub 2}O, and CO has been investigated. Dilute NO{sub 2} mixtures were excited by a pulse from an excimer pumped dye laser operating at 495 nm. The {nu}{sub 3} antisymmetric stretching modes of CO{sub 2} (2349 cm{sup {minus}1}) and N{sub 2}O (2223 cm{sup {minus}1}) and the {ital v}=1 level of CO (2143 cm{sup {minus}1}) were probed with continuous wave IR diode lasers. The amount of energy transferred from excited NO{sub 2} to the {nu}{sub 3} modes of both CO{sub 2} and N{sub 2}O was found to be 3%{plus minus}1% of the original excitation energy. On the other hand, a smaller amount of energy (0.9%{plus minus}0.3%) was deposited into the CO vibrational mode for NO{sub 2} contained in a dilute CO bath. These results support a picture of very inefficient transfer from high energy states of donor molecules to the high-frequency vibrational modes of small bath molecules. Differences in the efficiency of energy reception by the high-frequency modes of these three molecules scale roughly as the infrared transition moments for the bath states indicating the importance of resonance effects in the energy transfer process, but a combination of short- and long-range force mechanisms is probably necessary to account for the observed differences.
- OSTI ID:
- 5249826
- Journal Information:
- Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 91:9; ISSN JCPSA; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
DE-EXCITATION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUORESCENCE
LASER RADIATION
LUMINESCENCE
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NITROUS OXIDE
OXIDES
OXYGEN COMPOUNDS
QUENCHING
RADIATIONLESS DECAY
RADIATIONS
RELAXATION
RESONANCE
TRANSITION AMPLITUDES
VIBRATIONAL STATES