Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] aclb_v2_0.gz(81 Kbytes)|
|Manuscript Title: RAD-TRAP 2, a program for the solution of the Holstein equation of radiation trapping.|
|Authors: A.F. Molisch, B.P. Oehry, W. Schupita, G. Magerl|
|Program title: RAD-TRAP 2|
|Catalogue identifier: ACLB_v2_0|
Distribution format: gz
|Journal reference: Comput. Phys. Commun. 77(1993)255|
|Programming language: Fortran.|
|Computer: VAX 3100.|
|Operating system: VMS, MS-DOS 5.0.|
|RAM: 500K words|
|Word size: 32|
|Keywords: Trapping radiation, Radiative transfer, Fredholm integral Equations, Lifetime measurements, Lineshape measurements, Eigenvalues, Steady-state Distribution of excited Atoms, Emergent spectra.|
Nature of problem:
Computation of the eigenvalues and eigenfunctions of the Holstein integral equation (describing radiation trapping in an atomic vapor) and the steady-state distribution of excited atoms in one-dimensional geometries.
Reduction of the Fredholm integral equation of the second kind to an algebraic system of equations which is solved by standard methods.
Reasons for new version:
We have developed a new algorithm for the computation of the matrix elements for all the computations in the cylinder case; this new algorithm offers very high accuracy at still reasonable run time. Furthermore, the computation of the steady-state distribution of excited atoms and the computation of the emergent spectra are additional convenient features. The new version requires fewer NAGLIB routines and thus can be run also on a PC.
Restrictions of the achievable accuracy by memory and run-time limitations.
Uses subroutines from a standard library of mathematical subprograms, NAGLIB. The program is divided into 6 modules that must be compiled and linked separately.
Strongly dependent on the chosen geometry, the lineshape, the opacity and especially the required accuracy; will be between 1 and 1000 CPU seconds in most practical cases on a VAX 3100, or an IBM-PC (486/66MHz).
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