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Manuscript Title: DVR3D: a program suite for the calculation of rotation-vibration spectra of triatomic molecules (ROTLEV3).
Authors: J. Tennyson, M.A. Kostin, P. Barletta, G.J. Harris, O.L. Polyansky, J. Ramanlal, N.F. Zobov.
Program title: ROTLEV3
Catalogue identifier: ADTC
Journal reference: Comput. Phys. Commun. 163(2004)85
Programming language: Fortran 90.
Computer: PC, Compaq, Sunfire V750, V880, IBM p690, Origin 2000.
Operating system: UNIX, Linux, AIX.
RAM: Case dependent.
Keywords: Molecular spectra, Infrared, Microwave, Variational principle, Expectation values, Born-Oppenheimer approximation, Triatomic molecules.
PACS: 33.20, 39.30.
Classification: 16.3.

Subprograms used:
Cat Id Title Reference
ADTB DVR3DRJZ CPC 163(2004)85

Other versions:
Cat Id Title Reference
ADAL ROTLEV3 CPC 86(1995)175

Nature of problem:
ROTLEV3 performs the second step in a two-step variational calculation for the bound ro-vibrational levels of a triatomic system represented in either Jacobi or unsymmetrised Radau coordinates.

Solution method:
A basis is constructed from the solutions of the Coriolis decoupled problem provided by DVR3DRJZ. The angular coordinate is transformed back to a basis set representation. The sparse Hamiltonian matrix can be diagonalised iteratively or in core.

The size of matrix that can practically be diagonalised.

Unusual features:
Most data is read directly from DVR3DRJZ. ROTLEV3 can provide data to drive DIPOLE3 and/or XPECT3.

Additional comments:
The code has been extensively vectorised. A parallel version of the code, PROTLEV3 has been developed [1], contact the first author for details.
ROTLEV3 forms part of the DVR3D suite of programs. The complete suite is catalogued under the identifier ADTI. The tar.gz file for ADTI contains sample input and output data which can be used to test all the programs in the suite.

Running time:
Case dependent. The sample data takes less than a minute on a fast PC.

[1] H.Y. Mussa and J. Tennyson, Computer Phys. Comms., 128, 434(2000).