scholarly journals Distorted-wave Born Approximation for the Ionisation of Hydrogen by Electrons

1990 ◽  
Vol 43 (3) ◽  
pp. 291 ◽  
Author(s):  
IE McCarthy ◽  
X Zhang

Matrix elements for ionisation play an important part in electron-atom scattering calculations. Two methods for describing ionisation that can be incorporated into a scattering calculation are tested here against coplanar asymmetric experimental differential cross sections at 150 and 250 eV. They are the distorted-wave Born approximation and the coupled pseudostates method. A method that incorporates the exact boundary condition for three charged bodies describes the data significantly better and shows an important direction for improvement of scattering calculations.

1995 ◽  
Vol 73 (1-2) ◽  
pp. 74-84 ◽  
Author(s):  
D. Baddou ◽  
C. Rioux ◽  
R. J. Slobodrian ◽  
J. M. Nelson

Angular distributions of the differential cross sections and analysing powers were measured at an energy of 4.6 MeV. The results are compared with the distorted wave Born approximation predictions for two-nucleon transfer and for a deuteron-cluster transfer. The agreement is qualitative at best, and a discussion of alternatives to improve it is presented.


2009 ◽  
Vol 18 (07) ◽  
pp. 1483-1496 ◽  
Author(s):  
M. A. RAHMAN ◽  
M. S. CHOWDHURY

The 97 Mo (t,p)99 Mo reaction has been studied with the triton beam energy of 12 MeV obtained from tandem Van de Graaff accelerator at the Atomic Weapon Research Establishment, Aldermaston. Proton spectra were obtained at 12 different angles from 5° to 87.5° at an interval of 7.5° and were detected in nuclear emulsion plates. Angular distributions for transitions to 46 levels in the energy range from 0 to 2.054 MeV have been measured. Absolute differential cross-sections for the levels have been measured. The experimental angular distributions are compared with the distorted-wave Born approximation calculations (DWBA) to determine L and Jπ values. The present results are compared with the previous experimental results and model predictions.


2008 ◽  
Vol 17 (06) ◽  
pp. 1141-1156 ◽  
Author(s):  
M. A. RAHMAN ◽  
M. S. CHOWDHURY

The 97 Mo nucleus has been studied with the reaction 95 Mo (t, p) 97 Mo using a multichannel magnetic spectrograph. The isotopically enriched thin target 95 Mo was bombarded with the 12 MeV triton beam obtained from the tandem Van de Graaff accelerator at the Atomic Weapon Research Establishment, Aldermaston. Proton spectra are obtained at 12 different angles from 5° to 87.5° at an interval of 7.5° and are detected in nuclear emulsion plates. Forty-eight levels in the energy range from 0.000 to 3.189 MeV have been observed. Absolute differential cross-sections for these levels have been measured. The angular distributions are compared with the theoretical distorted-wave Born approximation calculations to determine L and Jπ values. The nuclear properties of 97 Mo are compared with previous experimental results and model predictions.


1981 ◽  
Vol 59 (2) ◽  
pp. 231-237 ◽  
Author(s):  
J. J. Bevelacqua ◽  
S. V. Prewett

Zero-range distorted-wave Born approximation calculations are used to investigate the systematics of two-nucleon transfer reactions. The shapes of the calculated 40Ca(t,p)42Ca(gs) and 208Pb(p,t)206Pb(gs) cross sections are relatively insensitive to details of the core plus two-neutron form factor, if the form factor tails have similar shapes. Studies of heavy targets such as 206Pb suggest a surface reaction mechanism, but lighter targets (16O and 40Ca) indicate that spatial regions beyond the target surface provide the dominant contribution to the (p,t) cross section.


1976 ◽  
Vol 54 (13) ◽  
pp. 1328-1342 ◽  
Author(s):  
R. F. Snider ◽  
R. E. Turner

The superoperator form of the collision cross section is evaluated within the distorted wave Born approximation. It is first verified that the obvious expansion methods give a result identical to that obtained by standard methods. Formalistically, the algebraic expansions of the transition operator and superoperator are shown to have parallel structures. The distorted wave Born approximation for the cross section also has a structure parallel to the structure of the Born approximation cross section. This is especially brought out by formulating the results in terms of time correlation functions. Certain simplifying features are found for cross sections averaged over initial and final velocity directions. These cross sections for internal state transitions are further simplified by averaging over a Maxwellian distribution of initial velocities in such a way as to obtain 'kinetic cross sections' appropriate for gas kinetic phenomena. Connection is also made with the 'constant acceleration approximation' used to estimate correlation functions in gas phase NMR.


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