Directory: gamma/ File: gamma-strength-analytic.readme (October 2, 2002) ------------------------------------------------------- gamma-strength-analytic.tgz Code for calculation of E1 gamma-strength functions (provided by V. Plujko on October 2, 2002) (adapted to UNIX by M. Herman) ***************************************************** Content ------- FORTRAN subroutine gamma-strength-analytic.f for calculation of E1-gamma strength functions for gamma-decay and photo-absorption at fixed excitation and gamma-ray energy along with the auxiliary routines and data files for running test calculations. The radiative strength functions can be calculated within the framework of any of the following models: SLO - Lorentzian with the energy-independent width [1] (Ch.6). EGLO - Enhanced generalized Lorentzian model [1] (Ch.6),[2]. GFL - Generalized Fermi liquid model [3] with extension for gamma- ray energies near GDR-energies. The term '(Egamma*Gamma_g^m(Egamma,T,beta)**2'was added to the dominator of the Eq.(5) [3] to avoid singularity near GDR-energies in a way similar to the other models for E1 strength. The calculations in the case of non even-even nuclei are performed with the use of the quantity 'S2Plus=(E2+)*beta**2' as input parameter or with the global parameterization: S2Plus=(E2+)*beta**2 = 217.16/A**2 (see, Eqs.(2) and (13) of [10]). MLO1 - Modified Lorentzian model corresponding to the thermodynamic pole approximation (TPA)[4-6] derived with micro-canonical ensemble for initial states [7]. The response function width is calculated within semi-classical second RPA and with collisional relaxation time based on the doorway state mechanism of the relaxation [8]. MLO2 - Modified Lorentzian model corresponding to the TPA approach with response function width within the extended Steinwedel- Jensen model with friction (ESJ) [9] and with collisional relaxation time based on the doorway state mechanism of the relaxation. MLO3 - Modified Lorentzian model corresponding to the TPA approach with the response function width within the ESJ model and with collisional relaxation time according to the Fermi-liquid theory. Files ----- gamma-strength-analytic.tgz contains: - gamma-strength-analytic.f : FORTRAN source of the subroutine and auxiliary files for stand-alone testing: - main.f : main code preparing input data and calling gamma-strength-analytic.f - densitydata.f : extracts level density parameters - gdrgfldata.f : assigns GDR parameters and deformations needed for the GFL model - temperature.f : calculates nuclear temperature - beijingn.dat : compilation of experimental GDR parameters - deflib.dat : deformation parameter (|beta2|) for the first collective 2+ level - defeff.dat : excitation energy and deformation parameter (beta) for the first collective 2+ level [10] - denslib.dat : level density parameters (BSFGM) - gnuplot.ini : input/output file to be used with gnuplot to obtain plots of gamma-strength functions by typing: gnuplot load 'gnuplot.ini' Input description ----------------- The subroutine GAMMA_STRENGTH, contained in the gamma-strength-analytic.f file is prepared for being called from any nuclear reaction code in order to calculate the dipole radiative strength function. The arguments of the subroutine are the following: Znucleus : atomic number of a nucleus Anucleus : mass number of a nucleus Eexcit : - initial state excitation energy (for gamma-decay) - excitation energy of the absorbing nucleus (for photo-absorption) Egamma : gamma-ray energy Temperf : nuclear temperature at: - Eexcit-Egamma for gamma-decay - Eexcit for photo-absorption Keyshape : key to specify strength-function model to be used: - 1 for MLO1 - 2 for MLO2 - 3 for MLO3 - 4 for EGLO - 5 for GFL - 6 for SLO The remaining input parameters must be transfered through the commons: COMMON /PARGDR/ EG1, GW1, CS1, EG2, GW2, CS2, NG COMMON /GFLPARAM/ BETagfl2, S2Plusgfl where: EG1 : energy of the first peak GW1 : full width of the first peak at half-maximum CS1 : peak cross section of the first peak EG2 : energy of the second peak CS2 : peak cross section of the second peak GW2 : full width of the second peak at half-maximum CS2 : peak cross section of the second peak NG : 1 for a single peak (spherical nucleus) 2 for double peaks (deformed nucleus) BETagfl2 : square of "deformation" parameter 'beta' associated with the nuclear quadrupole moment S2Plusgfl: product of first-excited 2+ state energy (in MeV) and the square of the deformation parameter ((E2+)*beta**2) [see, S.Raman,C.W.Nestor,Jr, P.Tikkanen, Atom. Data Nucl. Data Tabl. 78(2001)1 for beta and E2+ values] Running a stand-alone code -------------------------- Compile all FORTRAN sources, for example with: g77 -o gstrength *.f and type: gstrength to run the code. Type nucleus A and Z when requested. The results will be stored in a number of files with extension 'dat', separately for each gamma strength-function model, and in the summary file rsf_E.dat. Plots can be obtained by typing: gnuplot load 'gnuplot.ini' providing 'gnuplot' package is installed on the system. When running the stand-alone version the GDR parameters are initially searched in the beijingn.dat file. This file is numerically equivalent with the gdr-parameters-exp.dat file of RIPL-2. If more than one experimental data set for a given nuclide is listed the first entry in beijingn.dat is taken. Only if experimental data are absent, the GDR parameters are calculated by global systematics with effective quadrupole deformation parameters based on the mass-frdm95.dat file. The parameters of the GFL model (E2+ and 'beta') are searched in the defeff.dat file. This file is based on Table 1 of Ref. 10. If 'beta' is absent in the defeff.dat file a value (|beta2|) from the deflib.dat file is used. If all these fails, global parameterization S2Plus = (E2+)*beta**2 = 217.16/A**2 is invoked (see, Eqs.(2),(13) of [10]). The level density parameters ('a' and 'backshift') are taken from: (i) denslib.dat file based on the beijing_bs1.dat file of RIPL-1 using rigid-body moment inertia, (ii) systematics of von Egidy et al. [11] (Eq.10). NOTE: these back-shifted Fermi-gas model parameters are not consistent with the RIPL-2 recommendations. Format ------ Tarred and gzipped archive. On UNIX/Linux systems use tar xvzf gamma-strength-analytic.tgz or gunzip gamma-strength-analytic.tgz tar xvf gamma-strength-analytic.tar to explode the archive. On MS Windows WinZip should be used instead. Platform -------- Code is running on Linux/UNIX and MS Windows, other platforms with FORTRAN compiler are likely to work. Testing ------- Code was tested by M. Herman on Red Hat 7.3 Linux with g77 compiler. References ---------- [1] Handbook for calculations of nuclear reaction data.RIPL.IAEA- TECDOC-1034, August 1998; http: //www-nds.iaea.or.at /ripl/. [2] J. Kopecky, M. Uhl, R. E. Chrien, Phys.Rev. C47(1993)312. [3] S. F. Mughabghab, C. L. Dunford, Phys.Lett.B487(2000)155. [4] V. A. Plujko. Nucl.Phys. A649(1999)209c. [5] V. A. Plujko, Acta Phys. Pol. B31(2000)435. [6] V. A. Plujko, Proceedings of the 9 th Inter. Conf.Nucl. Reaction Mechanisms, Varenna, June 5- 9, 2000. Ed. E. Gadioli. Universita' degli Studi di Milano, Suppl. N.115, 2000, pp.113- 124. [7] V. A. Plujko (Plyuiko), Yad.Fiz. 52(1990)1004 [Sov. J. Nucl. Phys. 52(1990)639]. [8] V. A. Plujko,O.M. Gorbachenko, M.O. Kavatsyuk. Acta Phys. Slov., 51(2001)231. [9] J. M. Eisenberg, W. Greiner, Nuclear Theory, v.1, Nuclear Models, Collective and Single-Particle Phenomena, North-Holl., Amsterdam, 1987. Ch. 14, \S \S 3-5. [10] S. Raman, C. W. Nestor,Jr, P. Tikkanen, Atom.Data Nucl.Data Tabl. 78(2001)1. [11] T. Von Egidy, H. H. Schmidt, A. N. Behkami, Nucl.Phys.A481(1988)189.