Studies of atoms and molecules using multiphoton absorption of ultraviolet laser radiation

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5909494

Kligler, D J

The basic technique involves observation of fluorescent emission from gas samples irradiated by an ArF (193 nm) or KrF (248 nm) laser. First, collisional and photoabsorption properties of electronically excited H/sub 2/ are studied by means of selective excitation of the H/sub 2/ E,F /sup 1/..sigma../sub g//sup +/ double minimum state. The v = 2 level of the inner minimum of the E,F state is populated by two-photon absorption of ArF* laser radiation at 193 nm. The densities of the E,F rovibrational levels are measured by monitoring the near infrared E,F /sup 1/..sigma../sub g//sup +/ ..-->.. B /sup 1/..sigma../sub u//sup +/ fluorescent emission. Cross sections for ground state two-photon absorption to the E,F state and three-photon ionization are experimentally determined and are compared to calculated values. The E,F radiative life-time and collisional electronic and rotational relaxation rates are measured. The large electronic quenching cross sections (approx. 100 A/sup 3/) observed are attributed to collisional population of the C /sup 1/PI/sub u/ state, which is nearly degenerate with the E,F inner minimum. A theoretical model of inelastic scattering of H/sub 2/ E,F /sup 1/..sigma../sub g//sup +/ is developed and compared to experimental results. Two-photon excitation of Xe (5p/sup 5/6p) at 248 nm and of Xe/sup +/ and Kr (4p/sup 5/6p) at 193 nm forms the basis for another group of experiments.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 5909494
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
CROSS SECTIONS
DENSITY
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION SPECTROSCOPY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUIDS
FLUORESCENCE SPECTROSCOPY
GAS LASERS
GASES
HYDROGEN
INELASTIC SCATTERING
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONIZATION
LASER RADIATION
LASERS
MATHEMATICAL MODELS
MOLECULE COLLISIONS
MONITORING
NONMETALS
PHOTOIONIZATION
PHYSICAL PROPERTIES
RADIATIONS
RELAXATION
SCATTERING
SPECTROSCOPY
TIME DEPENDENCE
VIBRATIONAL STATES