Electron excitation cross sections of the 2p/sup 5/3s levels of neon

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5004467

Phillips, M H

The electron excitation cross sections of the four 2p/sup 5/3s levels of neon are measured by means of a new technique using laser induced fluorescenc. The values of both the apparent and direct excitatiuon cross sections are given as a function of incident electron energy (0-100eV for 1s/sub 3/ and 1s/sub 5/ metastable levels and 0-300 eV for the 1s/sub 2/ and 1s/sub 4/ resonance levels). The metastable levels are triplet states and their cross sections are sharply peaked. At the peak, 30 eV, the measured values of the cross sections are 0.59 x 10/sup -18/ cm/sup 2/ for the 1s/sub 3/ level and 3.2 x 10/sup -18/ cm/sup 2/ for the 1s/sub 5/ level. The 1s/sub 2/ and 1s/sub 4/ levels are mixtures of singlet and triplet states, and the cross sections are broad and peak at 60 eV. The apparent cross sections at 60 eV are 13.5 x 10/sup -18/ cm/sup 2/ for the 1s/sub 2/ level and 2.9 x 10/sup -18/ cm/sup 2/ for the 1s/sub 4/ level. Measurement of the atomic number density of each of the 1s levels is performed using the pulsed laser induced fluorescence. The measured values of the number density and the excitation cross section are used to obtain the lifetime of each level. The measured value of the reciprocal of the 1s/sub 3/ and 1s/sub 5/ lifetime is 1 x 10/sup 5/s/sup -1/. The 1s/sub 2/ and 1s/sub 4/ levels are radiation trapped, and the reciprocals of their lifetimes are 4 x 10/sup 5/s/sup -1/ and 3 x 10/sup 5/s/sup -1/ respectively. The electron excitation cross sections of the magnetic sublevels of each 1s level are obtained by measuring the polarization of the laser induced fluorescence as a function of laser polarization. The excitation cross sections of each of the magnetic sublevels within a particular 1s level are equal within experimental uncertainty.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 5004467
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 01-10
EV RANGE 10-100
EV RANGE 100-1000
EXCITATION
FLUIDS
FLUORESCENCE
GASES
LIFETIME
LUMINESCENCE
NEON
NONMETALS
RARE GASES