Systematics of K-Auger electron production by 4-8 MeV carbon ions following collisions with gas targets

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6046446

Anthony, J M

Absolute carbon K-Auger production cross sections for transitions with emitter rest frame energies between 200 and 300 eV were measured following 4 to 8 MeV collisions with H{sub 2}, He, Ne, and Ar at observation angles between 9.6{degree} and 10.6{degree} in the laboratory frame of reference. Spectra were measured using the high resolution projectile electron spectrometer (HRPES). For incident beams of two electron ions (C{sup 4+}), single electron capture into various {eta}, {ell} orbital vacancies ({eta} {ge} 2) of incident C{sup 4+}(1s2s {sup 3}S) metastable ions was the primary mechanism giving rise to the observed transitions. Cross section measurements for single electron capture into n {ge} 2, n=2 and n {ge} 3 shells are presented and compared with a semiclassical Bohr-Lindhardt calculation. High resolution spectra showed that the 1s(2sp2P {sup 3}P){sup 2}P - 1s{sup 2} {sup 1}S transition was 2.7 times more intense than the 1s(2s2p {sup 1}P){sup 2}P - 1s{sup 2} {sup 1}S transition, while the ratio of fractional parentage coefficients for these configurations is 3.00. The 1s2s{sup 2}{sup 2}S - 1s{sup 2}{sup 1}S transition was only 12% as intense as the 1s(2s2p{sup 3}P){sup 2}P - 1s{sup 2}{sup 1}S transition but increased to 45% at 8 MeV. Assuming that electron capture into all L-shell orbital vacancies is equally probable, the 1s2s{sup 2} {sup 2}S - 1s{sup 2} {sup 1}S transition, which results from capture into the single 1s vacancy of the incident 1s2s {sup 3}S ions, should be equal in intensity to the 1s(2s2p {sup 3}P){sup 2}P - 1s{sup 2} {sup 1}S transition, which occurs 1/6 of the time when an electron is captured into one of the 6 2sp vacancies. Suppression of capture into the 2s subshell is thought to be due to the presence of the 2s spectator electron in the incident metastable ions.

• Research Organization: North Carolina State Univ., Raleigh, NC (USA)
• OSTI ID: 6046446
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
BEAMS
CAPTURE
CARBON IONS
CATIONS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
ELECTRON CAPTURE
ELECTRON SPECTROMETERS
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUIDS
GASES
HELIUM
HYDROGEN
ION BEAMS
ION COLLISIONS
ION-ATOM COLLISIONS
ION-MOLECULE COLLISIONS
IONS
MEASURING INSTRUMENTS
MEV RANGE
MEV RANGE 01-10
MOLECULE COLLISIONS
NEON
NONMETALS
RARE GASES
SPECTRA
SPECTROMETERS