ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The log-derivative algorithm of Johnson is further generalized to evaluate transition amplitudes of orders up to third between states of free or bound character. These quantities appear in particular as constituents of a variety of low-order variational expressions for the reactance matrix which are based on the Lippmann–Schwinger type equations of scattering theory. The new algorithm is exploited to investigate relative accuracy of a number of these expressions on simple inelastic scattering test problems. Some findings of previous investigations, e.g., that of superior convergence of the expressions involving expansions of the amplitude density over the expressions based on expansions of the wave function, are revised. Superiority of the symmetric expressions over the asymmetric ones is demonstrated. The features of the new algorithm, such as relatively high efficiency and low storage requirements, make it well suited to variational calculations for reactive scattering. An exemplary implementation is presented to solving the Baer–Kouri–Levin–Tobocman (BKLT) equations for the collinear H+H2(arrow-right-and-left)H2+H reaction. Two new elements which improve the previous numerical treatment of these equations are exposed: the use of the Schwinger variational expression for the reactance matrix instead of the expression of the method of moments for the amplitude density and the use of distortion potentials producing inelastic transitions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.459190
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