Optical absorption spectra and kinetic behavior of helium excited diatomic molecule (a /sup 3/. sigma. /sub u//sup +/)

Journal Article · Tue Jul 01 00:00:00 EDT 1980 · J. Chem. Phys.; (United States)

OSTI ID:5258419

Takao, S; Kogoma, M; Oka, T; Imamura, M; Arai, S

The transient absorption spectra of electron-irradiated 12-atm helium have been measured in the wavelength region 3000--11 000 A. The observed molecular absorptions correspond to the c /sup 3/..sigma../sub g//sup +/reverse arrowa /sup 3/..sigma../sub u//sup +/, e /sup 3/Pi/sub g/reverse arrowa /sup 3/..sigma../sub u//sup +/, and i /sup 3/Pi/sub g/reverse arrowa /sup 3/..sigma../sub u//sup +/ transitions, short-lived atomic absorptions arising from He*(2/sup 3/S) being observed at several wavelengths. The rotational temperature of He*/sub 2/(a /sup 3/..sigma../sup +//sub u/, v''=0) produced initially is estimated to be room temperature from the intensity distribution of the P branch. The vibrational deactivation rate of He*/sub 2/(a /sup 3/..sigma../sub u//sup +/, v''=1) depends linearly on helium pressure, the rate constant being 1.0 x 10/sup -14/ cm/sup 3/ sec/sup -1/. The rate constants of the quenching reactions of He*/sub 2/(a /sup 3/..sigma../sub u//sup +/, v''=0) by Ne, Ar, Kr, Xe, H/sub 2/, N/sub 2/, O/sub 2/, CO, NO, N/sub 2/O, and CO/sub 2/ have been determined from time-dependent measurements of the absorption decay. The rate constants range from 0.4 x 10/sup -10/ cm/sup 3/ sec/sup -1/ for Ne to 1.0 x 10/sup -9/ cm/sup 3/ sec/sup -1/ for CO/sub 2/. An intense emission and absorption were observed at 7772 A in the quenching processes of He*/sub 2/(a /sup 3/..sigma../sub u//sup +/, v''=0) by oxygen-containing compounds.

• Research Organization: The Institute of Physical and Chemical Research, Wako-shi, Saitama 351, Japan
• OSTI ID: 5258419
• Journal Information: J. Chem. Phys.; (United States), Vol. 73:1
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ELECTRON-ATOM COLLISIONS
EXCITATION
HELIUM
ABSORPTION SPECTRA
ENERGY-LEVEL TRANSITIONS
HIGH PRESSURE
KINETICS
MOLECULES
ATOM COLLISIONS
COLLISIONS
CRYOGENIC FLUIDS
ELECTRON COLLISIONS
ELEMENTS
FLUIDS
NONMETALS
RARE GASES
SPECTRA
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena
640302 - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory