Exact second Born calculations for electron capture for systems with various projectile and target charges

Journal Article · Sat Oct 01 00:00:00 EDT 1983 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.28.2104· OSTI ID:5457321

McGuire, J H; Eichler, J; Simony, P R

Results of exact numerical calculations of differential and total 1s-1s electron-capture cross sections evaluated in the second Born approximation are presented for targets and projectiles of various charges Z/sub T/ and Z/sub P/ at velocities between 10 and 200 MeV/amu. For symmetric systems with Z/sub P/ = Z/sub T/ = Z the Thomas peak in the differential cross section, characteristic of a free-wave second Born-approximation process, appears at velocities above Z/sup 2/ x (5 MeV/amu), where Z is the nuclear charge of the target (or projectile). The shape of this Thomas peak contains information about real and virtual intermediate states of the system. For total cross sections at velocities below Z/sup 2/ x (2 MeV) the second Born-approximation cross section is larger than the first Born-approximation cross section indicating a breakdown of the second Born approximation using the free-wave Green's function. Results using the peaking approximation of Drisko converge to our exact second Born-approximation results only at velocities well above Z/sup 2/ x (10 MeV/amu). For systems asymmetric in Z/sub P/ and Z/sub T/ no exact scaling is found, although the systematics are qualitatively similar to the symmetric case using Z = 1/2(Z/sub P/+Z/sub T/). For p+Ne at 100 MeV, the exact Born-approximation results lie somewhat above exact impulse-approximation calculations. It is found that the peaking approximation of Briggs and Simony converges to exact second Born-approximation results as the asymmetry of the projectile and target charges increases.

• Research Organization: Fachbereich Physik, Hahn-Meitner Institut, D-1000 Berlin 39, West Germany
• OSTI ID: 5457321
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 28:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
BORN APPROXIMATION
CAPTURE
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELECTRON CAPTURE
ENERGY RANGE
ION COLLISIONS
ION-ATOM COLLISIONS
MASS NUMBER
MEV RANGE
MEV RANGE 10-100
TOTAL CROSS SECTIONS