A Pascal program for calculating the reduced Coulomb Green's functions and their partial waves
✍ Scribed by J. Mlodzki; J. Kuszkowski; M. Suffczynski
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 469 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0010-4655
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✦ Synopsis
RCGF Hamiltonian is decomposed into terms of definite angular momentum it is useful to have the partial waves of the Green's Catalogue number: ACEP function. We therefore present a program for calculating the functions in question. Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland (see application form in this issue) Methed of solution The formulae for the reduced Coulomb Green's function and Computer: CDC 6000; Installation: Computer Centre its partial waves are lengthy and tedious to evaluate [1,2]. CYFRONET, Institute of Nuclear Research, Otwock, ~wierk However, these functions can be expressed in terms of poly-05-400, Poland nomials multiplied by known transcendental functions: cxponentials, an exponential integral and a logarithm. The main Operating system: SCOPE 3.4.4 task of the program is to evaluate the coefficients of the polynomials. It is worth stressing that the results are purely Programming language used: PASCAL 6000 analytical and exact because of the use of special data structures, for example a fraction represented by a pair of integers High speed storage reiuired: 54000~words or a polynomial by an array of fractions. No. of bits in a word: 60 Restrictions on the complexity of the problem Peripheralused: card reader, lineprinter The value of the main quantum number n ranges from 1 to 7, and that of the angular momentum quantum number I from 0 No. of cards in combined program and test deck: 1385 to 7. These restrictions are caused by the limitations of integer arithmetic implemented in the computer used. Cardpunching code: EBCDIC/029 Typical running time Keywords: reduced Coulomb Green's function, perturbation Compilation -11 s, evaluation of the reduced function -1.6 s, theory, hydrogen-like atoms evaluation of the partial wave -0.8 s. Nature of physical problem The reduced Coulomb Green's function is the coordinate space References representation of the sum over intermediate states encountered [1] A. Lusakowski and M. Suffczynski, Bull. Acad. Pol. Phys. in bound state second order perturbation theory. This function Astron. 28(2) (1980). does not depend on the particular perturbation problem. Thus, [2