H(2s) and H(2p) branching ratio in the photodissociation of H/sub 2/ near threshold

Journal Article · Tue Nov 01 00:00:00 EST 1977 · J. Chem. Phys.; (United States)

OSTI ID:7277787

Mentall, J E; Guyon, P M

The excitation spectrum for producing Lyman-..cap alpha.. fluorescence by photodissociating H/sub 2/ has been obtained with 0.12 A bandwidth in the dissociation threshold region. At 839 A, the peak in the fluorescence cross section, one observes Lyman-..cap alpha.. emission from several continuums and from the J=1 and J=2 predissociated rotational levels of the D /sup 1/Pi/sup +//sub u/(v'=3) state. At this wavelength the branching ratio sigma (2s)/(sigma (2s)+sigma (2p)) was obtained using a quenching field method. It was determined that 57% of the excited atoms are produced in the metastable 2 /sup 2/S/sub 1/2/ state. From a study of the fluorescence signal versus pressure a cross section of 0.9 x 10/sup -14/ cm/sup 2/ was derived from the chemi-ionization reaction H/sub 2/+H(2s) ..-->..H/sup +//sub 3/+e/sup -/.

• Research Organization: Equipe de Recherche No. 57 du C.N.R.S., Laboratoire de Photophysique Moleculaire, Universite Paris-sud, Batiment 213, 91405 Orsay, France
• OSTI ID: 7277787
• Journal Information: J. Chem. Phys.; (United States), Vol. 67:9
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN
DISSOCIATION
PHOTOLYSIS
BRANCHING RATIO
FLUORESCENCE
LYMAN LINES
P STATES
S STATES
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DECOMPOSITION
ELEMENTS
ENERGY LEVELS
FLUIDS
LUMINESCENCE
NONMETALS
PHOTOCHEMICAL REACTIONS
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory