Penning and associative ionization in the metastable helium--atomic deuterium system

Journal Article · Fri Dec 01 04:00:00 EST 1978 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.436513· OSTI ID:6657009

Neynaber, R H; Tang, S Y

Measurements of Penning and associative ionization cross sections (Q/sub PI/ and Q/sub AI/) and branching ratios (R) for the He*--D system have been repeated in this laboratory. The studies were made using a merging-beams technique for a relative kinetic energy W of the reactants from nominally 0.01 to 10 eV. This is a wider energy range than covered previously. The He* represents a composite of about 15% He(2 /sup 1/S) and 85% He(2 /sup 3/S). The new results are more acurate than the old due to improvements in the apparatus. From the new studies, a well depth of approximately 2.1 eV was obtained for the He(2 /sup 3/S) --D potential and between 0.25 and 0.4 eV for the He(2 /sup 1/S) --D potential. These well depths agree with values obtained by others. Laboratory-energy distributions of Penning ions indicate differences in the kinetics of reaction for He(2 /sup 1/S) and He(2 /sup 3/S). The new Q/sub AI/, Q/sub PI/, and R agree with those of several other experimenters although there are discrepancies in Q/sub PI/ and R with the calculations of Hickman and Morgner.

• Research Organization: IRT Corporation, San Diego, California 92138
• OSTI ID: 6657009
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 69:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-ATOM COLLISIONS
BEAMS
COLLISIONS
CRYOGENIC FLUIDS
DEUTERIUM
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 01-10
FLUIDS
HELIUM
HYDROGEN ISOTOPES
IONIZATION
ISOTOPES
LIGHT NUCLEI
MILLI EV RANGE
MOLECULAR BEAMS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PENNING EFFECT
RARE GASES
STABLE ISOTOPES