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Betrt-a procedure to evaluate the cross section for electron-hydrogen collisions in the bethe approximation to the reactance matrix

1987; Elsevier BV; Volume: 47; Issue: 2-3 Linguagem: Inglês

10.1016/0010-4655(87)90115-9

1879-2944

A. Burgess, Colm T. Whelan,

Advanced Chemical Physics Studies

Being motivated by the applied researchers’ persisting need for accurate scattering data for the collisions of electrons with hydrogen atoms, we developed a computer package–Hex–that is designed to provide trustworthy results for all basic discrete and continuous processes within non-relativistic framework. The package consists of several computational modules that implement different methods, valid for specific energy regimes. Results of the modules are kept in a common database in the unified form of low-level scattering data (partial-wave T-matrices) and accessed by an interface program which is able to produce various derived quantities like e.g. differential and integral cross sections. This article is the first one of a series of articles that are concerned with the implementation and testing of the modules. Here we give an overview of their structure and present (a) the command-line interface program hex-db that can be also easily compiled into a derived code or used as a backend for a web-page form and (b) simple illustrative module specialized for high energies, hex-dwba, that implements distorted and plane wave Born approximation.Program title: hex-dbCatalogue identifier: AETH_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETH_v1_0.htmlProgram obtainable from: CPC Program library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data etc.: 30367No. of bytes in distributed program, including test data etc.: 232032Distribution format: tar.gzProgramming language: C++11Operating system: Any system with a C++11 compiler (e.g. GCC 4.8.1; tested on OpenSUSE 13.1 and Windows 8).RAM: Test run 3 MiB.CPC Library Classification: 2.4 Electron scatteringExternal libraries:GSL [49], FFTW3[52], SQLite3 [46]. All of the libraries are open-source and maintained.Nature of problem: Extraction of derived (observable) quantities from partial-wave T-matrices.Method of solution: Simple algebraic operations and angular summations of the scattering T-matrices.Additional comments: Command-line interface to a database shared between several computational backends.Running time: Mostly less than a second.Program title: hex-dwbaCatalogue identifier: AETH_v1_0Program obtainable from: CPC Program library, Queen’s University, Belfast, N. IrelandProgramming language: C++11Operating system: Any system with a C++11 compiler (e.g. GCC 4.8.1; tested on OpenSUSE 13.1 and Windows 8).RAM: Test run 7.5 MiB.CPC Library Classification: 2.4 Electron scatteringExternal libraries:GSL [49], CLN [48], optionally HDF5[53]. All of the libraries are open-source and maintained.Nature of problem: Perturbative solution of electron–hydrogen scattering for high energies.Solution method: Born approximation of the first order, with optional distortion of partial waves by the target potential.Running time: Test run consisting of 60 successive launches of the program took 9 min on Intel Core i7-3770K 3.5 GHz.