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Collisions of electrons with hydrogen atoms I. Package outline and high energy code

2014; Elsevier BV; Volume: 185; Issue: 11 Linguagem: Inglês

10.1016/j.cpc.2014.05.031

1879-2944

Jakub Benda, Karel Houfek,

Electron and X-Ray Spectroscopy Techniques

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-db Catalogue identifier: AETH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETH_v1_0.html Program obtainable from: CPC Program library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data etc.: 30367 No. of bytes in distributed program, including test data etc.: 232032 Distribution format: tar.gz Programming language: C++11 Operating 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 scattering External 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-dwba Catalogue identifier: AETH_v1_0 Program obtainable from: CPC Program library, Queen’s University, Belfast, N. Ireland Programming language: C++11 Operating 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 scattering External 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.