Coulomb Lindhard approximation: Nonlinear excitation effects for fast ions penetrating a free-electron gas
- Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires, (Argentina)
We introduce a distorted wave method to calculate the nonlinear excitation effects occurring when a fast bare ion penetrates a free-electron gas. The central scheme of this work is to replace the undistorted plane waves leading to the Lindhard dielectric response function (or random phase approximation) by Coulomb waves with an effective charge. This impulse-type approximation is valid for velocities larger than the Fermi velocity. Stopping and mean free path are presented for impact of bare multicharged ions on aluminum free-electron gas. The Barkas effect is theoretically found, i.e., negative heavy particles lose energy at the lower rate than positive particles of the same velocity do. As the projectile charge increases, the single differential cross section per unit energy presents two effects: the plasmon peak sharpens and the binary peak starts to be increasingly noticeable.
- OSTI ID:
- 20640073
- Journal Information:
- Physical Review. A, Vol. 68, Issue 2; Other Information: DOI: 10.1103/PhysRevA.68.022904; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
ALUMINIUM
DIELECTRIC MATERIALS
DIFFERENTIAL CROSS SECTIONS
DISTORTED WAVE THEORY
EFFECTIVE CHARGE
ELECTRON GAS
ELECTRON-ATOM COLLISIONS
ENERGY LOSSES
EXCITATION
MEAN FREE PATH
MULTICHARGED IONS
NONLINEAR PROBLEMS
PULSES
RANDOM PHASE APPROXIMATION
RESPONSE FUNCTIONS
VELOCITY