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Weizmann shell model computational code
C-266 COMPUTER PHYSICS COMMUNICATIONS 8 (1974) 101-117. NORTH-HOLLAND PUBLISHING COMPANY
WEIZMANN SHELL MODEL COMPUTATIONAL CODE R. GROSS and Y. ACCAD The Weizmann Institute of Science, Rehovot, Israel Received 10 April 1974
PROGRAM SUMMARY Title of program: WSMCC Catalogue number: ABGN Computer: IBM 370/165; Installation: Weizmann Institute of Science, Israel
Operating system: OS360 Programming language used: FORTRAN IV h
speed storage required: 7000 words
No. of bits in a word: 32 Overlay structure: None No. of magnetic tapes required: One Other peripherals used: Caxd-reader and printer
and it is able to calculate any matrix element of a two-body scalar operator in one, two or three shells. For more than three shells, the program can be extended by recoupling the angular momenta of the n particles in the wave function so that all unchanged ( n - 2 ) particles will be coupled together (this extension is available, but is not included in the current version).
Restrictions on the complexity of the problem Calculations are done in double-precision mode (each number occupies two 32-bit words in memory). The above mentioned high speed storage size includes an array of about 6500 cfp's and a hamiltonian matrix of 45 by 45. In case of a larger matrix, the elements are written out as they are computed for later diagonalization.
No. of cards in combined program and test deck: 5695 Typical running time CPC Library subprograms used: Catalogue number: ABKB; Title: JJTCFP; Ref in CPC: 1 (1970) 225.
Keywords: Nuclear, cfp, wave functions, shell-model,]-/ coupling, seniority, spin, isospin, configuration, coupling, recoupling of angular momenta.
Nature of physical problem WSMCC is a computer program which carries out nuclear shell-model (spectroscopy) calculations. Given the total number of particles, total angular momentum and total isospin, the program calculates the energy levels and eigenstates as functions of the two-body matrix elements and the single particle energies.
Method of solution Calculations axe carried out by reducing the problem to the two-body matrix elements, using the weU-known shell-model formalism presented in ref. [1 ]. The current version of the program can handle large configurations as well as small ones,
Running time depends roughly on the square of the order of the hamiltonian matrix, the values of total and intermediate spins and isospins; number of particles and configurations; the spin of the configuration; whether the calculation is completed in core or not; whether the classification of the states is read in or calculated by the program; and many others. To give an order of magnitude for the running time we mention that for the calculation of the 21 states of 36At with zero angular momentum and isospin, the present version needs about 13 sec on an IBM 370[165; the same calculation for the 325 states (with J = 0 and T = 0) of 24Mg needs about 20 rain and for the 21 states of 2°Ne only 2 sec. So it is quite meaningless to speak about a "typical" running time.
Unusual features of the program The input coefficients of fractional parentage (cfp) cards can be taken with their original format from ref. [2]. Most of the subroutines can be used alone for different calculations using the shell-model formalism.
References [ 1 ] A. de Shalit and I. Talmi, Nuclear shell theory (Academic Press, New York, 1963). [2] L.B. Hubbard, Computer Phys. Commun. 1 (1970) 225.
WEIZMANN SHELL MODEL COMPUTATIONAL CODE R. GROSS and Y. ACCAD The Weizmann Institute of Science, Rehovot, Israel Received 10 April 1974
PROGRAM SUMMARY Title of program: WSMCC Catalogue number: ABGN Computer: IBM 370/165; Installation: Weizmann Institute of Science, Israel
Operating system: OS360 Programming language used: FORTRAN IV h
speed storage required: 7000 words
No. of bits in a word: 32 Overlay structure: None No. of magnetic tapes required: One Other peripherals used: Caxd-reader and printer
and it is able to calculate any matrix element of a two-body scalar operator in one, two or three shells. For more than three shells, the program can be extended by recoupling the angular momenta of the n particles in the wave function so that all unchanged ( n - 2 ) particles will be coupled together (this extension is available, but is not included in the current version).
Restrictions on the complexity of the problem Calculations are done in double-precision mode (each number occupies two 32-bit words in memory). The above mentioned high speed storage size includes an array of about 6500 cfp's and a hamiltonian matrix of 45 by 45. In case of a larger matrix, the elements are written out as they are computed for later diagonalization.
No. of cards in combined program and test deck: 5695 Typical running time CPC Library subprograms used: Catalogue number: ABKB; Title: JJTCFP; Ref in CPC: 1 (1970) 225.
Keywords: Nuclear, cfp, wave functions, shell-model,]-/ coupling, seniority, spin, isospin, configuration, coupling, recoupling of angular momenta.
Nature of physical problem WSMCC is a computer program which carries out nuclear shell-model (spectroscopy) calculations. Given the total number of particles, total angular momentum and total isospin, the program calculates the energy levels and eigenstates as functions of the two-body matrix elements and the single particle energies.
Method of solution Calculations axe carried out by reducing the problem to the two-body matrix elements, using the weU-known shell-model formalism presented in ref. [1 ]. The current version of the program can handle large configurations as well as small ones,
Running time depends roughly on the square of the order of the hamiltonian matrix, the values of total and intermediate spins and isospins; number of particles and configurations; the spin of the configuration; whether the calculation is completed in core or not; whether the classification of the states is read in or calculated by the program; and many others. To give an order of magnitude for the running time we mention that for the calculation of the 21 states of 36At with zero angular momentum and isospin, the present version needs about 13 sec on an IBM 370[165; the same calculation for the 325 states (with J = 0 and T = 0) of 24Mg needs about 20 rain and for the 21 states of 2°Ne only 2 sec. So it is quite meaningless to speak about a "typical" running time.
Unusual features of the program The input coefficients of fractional parentage (cfp) cards can be taken with their original format from ref. [2]. Most of the subroutines can be used alone for different calculations using the shell-model formalism.
References [ 1 ] A. de Shalit and I. Talmi, Nuclear shell theory (Academic Press, New York, 1963). [2] L.B. Hubbard, Computer Phys. Commun. 1 (1970) 225.