Theoretical calculation of Penning-ionization cross sections for collisions of He(2/sup 1,3/S) with sodium atoms
Cross sections have been calculated for the Penning ionization of ground-state sodium atoms in collisions with metastable He(2 /sup 1,3/S) atoms for the range of center-of-mass energies 0.01 eV < or =E< or =1.0 eV. The cross sections were calculated with use of optical-model potentials. The real parts of the relevant potential-energy curves were determined by carrying out a configuration-interaction (CI) calculation on the NaHe molecule. The potentials were adjusted to yield the correct asymptotic van der Waals form. The imaginary parts of the potentials correspond to autoionization rates and were obtained from a Stieltjes moment analysis of a discrete (L/sup 2/) representation of the e/sup -/+NaHe/sup +/ continuum, as represented by diffuse molecular orbitals generated by the CI procedure. The calculated cross section for He(2 /sup 3/S) on Na at E = 0.04 eV is in good agreement with stationary-afterglow measurements at room temperature. The singlet-to-triplet ratio of cross sections is in good agreement with that measured by beam techniques. Elastic differential cross sections for He(2 /sup 1/S) scattered from Na have also been calculated. Satisfactory agreement is obtained with recent crossed-beam measurements.
- Research Organization:
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
- OSTI ID:
- 5998146
- Journal Information:
- Phys. Rev. A; (United States), Vol. 31:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HELIUM
ATOM-ATOM COLLISIONS
ELASTIC SCATTERING
SODIUM
CONFIGURATION INTERACTION
DIFFERENTIAL CROSS SECTIONS
GROUND STATES
IONIZATION
METASTABLE STATES
MILLI EV RANGE
PENNING EFFECT
TRANSIENTS
VAN DER WAALS FORCES
ALKALI METALS
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
EV RANGE
EXCITED STATES
FLUIDS
GASES
METALS
NONMETALS
RARE GASES
SCATTERING
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena