Absolute emission cross sections for electron-impact excitation of Zn/sup +/(4p /sup 2/P) and (5s /sup 2/S) terms
Absolute emission cross sections for electron-impact excitation of the 3d/sup 10/4p /sup 2/P and 3d/sup 10/5s /sup 2/S terms of Zn/sup +/ have been measured from below threshold to about 790 eV /sup 2/P and 390 eV /sup 2/S using the crossed-charged-beams technique. Both transitions have the abrupt onset at threshold characteristic of positive-ion excitation. The /sup 2/P cross section shows considerable structure in the interval from threshold to near 20 eV, above which it falls off smoothly. Agreement with five-state close-coupling theory is excellent below 100 eV when cascading is included in the theory. Above 100 eV, the data lie above the theory. The peak value of the /sup 2/P cross section is 9.4 x 10/sup -16/ cm/sup 2/ essentially at threshold, while the peak value of the /sup 2/S cross section is about 0.47 x 10/sup -16/ cm/sup 2/. The net linear polarization of the 3d/sup 10/4p /sup 2/P emission was measured (unresolved from the 3d/sup 10/4d /sup 2/D..-->..3d/sup 10/4p /sup 2/P cascading transition), and these data were used to correct the cross-section data for anisotropy of the emitted light. The effective lifetime of the 3d/sup 9/4s/sup 2/ /sup 2/D/sub 3/2/ level was measured by observing exponential decay of the 589.6-nm photons resulting from its decay.
- Research Organization:
- Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, Boulder, Colorado 80309
- OSTI ID:
- 5424160
- Journal Information:
- Phys. Rev. A; (United States), Vol. 25:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ELECTRON-ION COLLISIONS
ENERGY-LEVEL TRANSITIONS
ZINC IONS
CASCADE SHOWERS
CROSS SECTIONS
EV RANGE 100-1000
EXCITATION
LIFETIME
POLARIZATION
CHARGED PARTICLES
COLLISIONS
ELECTRON COLLISIONS
ENERGY RANGE
EV RANGE
ION COLLISIONS
IONS
SHOWERS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena