Peak-power dependence of rovibronic populations below the quasicontinuum during IR multiphoton absorption

Conference · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6524299

Brenner, D M

Experimental studies on IR multiphoton absorption and dissociation have generally provided insight only into the relationship of IR laser characteristics such as power, wavelength, and mode structure to the observables dissociation yields, average number of photons absorbed, and product energy distribution. As a result, theoretical modeling of absorption at levels below the quasicontinuum has been based on facts somewhat removed from the actual phenomenon of interest. The experiments presented here provide information on the unperturbed rotational/vibrational populations of levels subsequent to IR excitation at levels below 4000 cm/sup -1/ of energy. The experiment makes use of molecular beam techniques in conjunction with IR-visible double resonance. A CO/sub 2/ laser of known pulse duration prepares vibrationally excited thiophosgene, Cl/sub 2/C = S. The absorbing transition is 2 ..nu../sub 4/. A tunable nitrogen-pumped dye laser scans the visible excitation spectrum to probe the perturbed rotational-vibrational populations of the pumped mode. Because the electronic transition is electric dipole forbidden, combination hot bands having the appropriate quantum numbers of the ground state are used in the analysis.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6524299
• Report Number(s): BNL-28758; CONF-810609-1
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTROSCOPY
CARBONIC ACID DERIVATIVES
DISSOCIATION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
EXCITED STATES
INFRARED RADIATION
LASER RADIATION
MATHEMATICAL MODELS
MOLECULES
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOSGENE
RADIATIONS
ROTATIONAL STATES
SPECTROSCOPY
VIBRATIONAL STATES