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Manuscript Title: DIRIGE: a program for calculating eigenvalues and initial values of log derivative eigenfunctions for a diatomic molecule.
Authors: M. Dagher, H. Kobeissi
Program title: DIRIGE
Catalogue identifier: AATT_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 46(1987)445
Programming language: Fortran.
Computer: IBM3090.
Operating system: VM/SP HPO.
RAM: 80K words
Word size: 64
Peripherals: disc.
Keywords: Molecular physics, Structure, Diatomic molecule, Born oppenheimer, Approximation, Rotation vibration, R-k-r potential, Theoretical potential, Canonical functions, Eigen-value equation, Eigenvalue, Log derivative, Eigenfunction.
Classification: 16.1.

Nature of problem:
The program presents a new treatment of the vibration-rotation eigenvalue problem for a diatomic molecule.

Solution method:
For any given potential, this method makes use of the canonical functions to derive an eigenvalue equation independent of the wave- function. The resolution of this equation is reduced to that of a simple and classical numerical problem.

Provided that the Born-Oppenheimer approximation is valid there are no known restrictions.

Unusual features:

Running time:
Dependent upon the number of levels to be calculated. 81 seconds for the test run.