Two-photon excitation and excited-state absorption cross sections for H/sub 2/ E,F /sup 1/. sigma. /sub g/ (v = 6): Measurement and calculations
The absolute two-photon excitation cross section for the H/sub 2/ E,F /sup 1/..sigma../sub g/ (v' = 6)left-arrowX/sup 1/..sigma../sub g/ (v'' = 0) Q(1) transition at 193 nm has been measured by observing the E,F /sup 1/..sigma../sub g//sup +/ (v' = 6)->B /sup 1/..sigma../sub u//sup +/ (v'' = 0) fluorescence at /similar to/750 nm. The measured integrated two-photon excitation cross section, (2.0 +- 0.9) x 10/sup -36/ cm/sup 4/, is in good agreement with the theoretical value of 2.8 x 10/sup -36/ cm/sup 4/, which is obtained from previously published calculations (Huo and Jaffe, Chem. Phys. Lett. 101, 463 (1983)). The absolute cross section for photoabsorption by the E,F state at 355 and 193 nm was also measured by monitoring the depletion of the 750-nm fluorescence caused by a second laser. The measured cross sections for photoabsorption by the E,F (v = 6) state are (9.7 +- 2.4) x 10/sup -18/ cm/sup 2/ at 355 nm and (6.4 +- 1.3) x 10/sup -18/ cm/sup 2/ at 193 nm. Comparison with theoretical estimates (Cohn, J. Chem. Phys. 57, 2456 (1972)) of the direct photoionization cross section of this state (8.5 x 10/sup -18/ cm/sup 2/ at 355 nm and 3.2 x 10/sup -18/ cm/sup 2/ at 193 nm) suggests that other processes may contribute to the photoabsorption.
- Research Organization:
- Molecular Physics Laboratory, SRI International, Menlo Park, California 94025
- OSTI ID:
- 6315436
- Journal Information:
- Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 39:8; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
COLLISIONS
CROSS SECTIONS
DATA
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
EXPERIMENTAL DATA
FREQUENCY DEPENDENCE
HYDROGEN
INFORMATION
IONIZATION
MOLECULE COLLISIONS
NONMETALS
NUMERICAL DATA
PHOTOIONIZATION
PHOTON COLLISIONS
PHOTON-MOLECULE COLLISIONS
RADIATIONS
ULTRAVIOLET RADIATION