Role of atomic resonances in the ionization of potassium atoms in slow collisions with He(2 /sup 1,3/S)
Cross sections have been calculated for the Penning ionization of ground-state potassium atoms in collisions with metastable He(2 /sup 1,3/S) atoms for the range of center-of-mass-system energies 0.01 eVless than or equal toEless than or equal to1.0 eV. The cross sections were calculated using ab initio ptical potentials. The real part of the optical potential was obtained by adjusting the potential curve resulting from a configuration-interaction (CI) calculation performed on the HeK molecule so as to include the correct van der Waals asymptotic form. The imaginary part was obtained by performing a Stieltjes moment analysis of a discrete (L/sup 2/) representation of the HeK/sup +/+e/sup -/ continuum generated in a CI procedure. The calculated cross section for He(2 /sup 3/S) scattered from K at E = 0.032 eV is in good agreement with stationary afterglow measurements at room temperature. A nearly degenerate core-excited state of potassium (which has a curve crossing with the He(2 /sup 3/S)K molecular state) is then explicitly included in a Landau-Zener formulation which further increases the calculated cross section, but it still agrees well with the room-temperature measurements. Elastic differential cross sections for He(2 /sup 1/S) on K are also reported.
- Research Organization:
- Theoretical Atomic and Molecular Physics Group, Physics Department, Lawrence Livermore National Laboratory, Livermore, California 94550
- OSTI ID:
- 6237214
- Journal Information:
- Phys. Rev. A; (United States), Vol. 36:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HELIUM
ATOM-ATOM COLLISIONS
POTASSIUM
PENNING EFFECT
CONFIGURATION INTERACTION
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
GROUND STATES
IONIZATION
METASTABLE STATES
ALKALI METALS
ATOM COLLISIONS
COLLISIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
METALS
NONMETALS
RARE GASES
SCATTERING
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena