Fast computation of close-coupling exchange integrals using polynomials in a tree representation

Abstract The semi-classical atomic-orbital close-coupling method is a well-known approach for the calculation of cross sections in ion–atom collisions. It strongly relies on the fast and stable computation of exchange integrals. We present an upgrade to earlier implementations of the Fourier-transform method. For this purpose, we implement an extensive library for symbolic storage of polynomials, relying on sophisticated tree structures to allow fast manipulation and numerically stable evaluation. Us... Title of program: TXINT Catalogue Id: AEHS_v1_0 Nature of problem Analytical calculation of one- and two-center exchange matrix elements for the close coupling method in the impact parameter model. Versions of this program held in the CPC repository in Mendeley Data AEHS_v1_0; TXINT; 10.1016/j.cpc.2010.10.027 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)