Angular differential cross sections for excitation of atomic hydrogen to its N = 2 level by impact of 15-100 keV He/sup +/ ions

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5280530

Aldag, J E

Differential cross section for excitation of atomic hydrogen to its n = 2 level by 15-100 keV He/sup +/ ions have been determned for c.m. angles from 0 to 8 mrad. The cross sections were obtained from an analysis of the angular distribution of the scattered ions which had lost an energy corresponding to the excitation of the target to its n = 2 level. The shape of the differential cross section changes rapidly with increasing incident energy. At 15 keV, the cross section changes rapidly with increasing incident energy. At 15 keV, the cross section falls off by a factor of 5 in 6 mrad. At 100 keV, the cross section decreases by nearly six orders or magnitude in the same angular range. The middle and high energy results are in good agreement with a recent Glauber approximation calculation for the scattering. Comparison of the present reduced cross section results with those at lower energy (0.75 to 1.5 keV) indicates that the collision mechanism is not the same. Excitation to n greater than or equal to 3 levels was clearly present in the energy-loss spectra for the process in contradiction to the molecular orbital description of the mechanism. Total cross section results are given for the same scattering process in the 15-200 keV range and are also in good agreement with the Glauber and VPSA theory results. The experimental and Glauber differential results, however, are clearly different at 25 keV.

• Research Organization: Missouri Univ., Columbia (USA)
• OSTI ID: 5280530
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
GLAUBER THEORY
HELIUM IONS
HYDROGEN
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
KEV RANGE 10-100
NONMETALS
SCATTERING