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Manuscript Title: COLLRAD: a code for calculating the quasi-steady state population densities of excited states of hydrogen-like ions.
Authors: G.J. Tallents
Program title: COLLRAD
Catalogue identifier: AAID_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 12(1976)205
Programming language: Fortran.
Computer: UNIVAC 1108, 1100/42.
Operating system: EXEC - 8.
RAM: 14K words
Word size: 36
Keywords: Collisional, Radiative, Recombination, Ionization, Hydrogen-like, Population density, Plasma physics, Atomic process.
Classification: 19.1.

Nature of problem:
The evaluation of the population densities of the lower quantum states of a plasma ion, in general, involves the simultaneous solution of the rate equations (one for each quantum state) containing the rates of the various collisional and radiative processes which polulate and depopulate each quantum state. The time independent case where quasi- steady state equilibrium is established has been considered.

Solution method:
COLLARD caluclates quantum state densities for hydrogen-like ions using the collisional-radiative model of Bates et al. Coefficients giving the population densities of the excited states, and the rate of change of the ground state density are calculated for input electron density and temperature by solving a set of simultaneous linear equations.

Restrictions:
Densities are calculated for excited quantum states in quasi-steady state equilibrium.

Unusual features:
COLLARD is written in standard FORTRAN, except for the use of the NAMELIST facility.

Running time:
For execution 1.7 s on the ANU UNIVAC 1100/42.