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Manuscript Title: A program suite for the calculation of ro-vibrational spectra of
triatomic molecules. | ||

Authors: J. Tennyson, S. Miller | ||

Program title: TRIATOM | ||

Catalogue identifier: ABJW_v1_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 55(1989)149 | ||

Programming language: Fortran. | ||

Computer: CRAY-1. | ||

Operating system: COS. | ||

Peripherals: disc. | ||

Keywords: Molecular physics, Vibration, Ro-vibrational, Body-fixed, Associated laguerre Polynomials, Associated legendre Polynomials, Gaussian quadrature, Variational, Close-coupled equations, Vectorised. | ||

Classification: 16.3. | ||

Subprograms used: | ||

Cat
Id | Title | Reference |

ABJX_v1_0 | SELECT | CPC 55(1989)149 |

Nature of problem:TRIATOM calculates the bound ro-vibrational levels of a triatomic system using the generalized body-fixed coordinates developed by Sutcliffe and Tennyson. | ||

Solution method:A basis is constructed as a product of radial (either Morse oscillator- like or spherical oscillator) functions and associated Legendre polynomials for the bending coordinate, with rotation matrices carrying the rotational motion. A secular matrix is constructed using Gaussian quadrature and diagonalised to give solutions. Input can be direct from SELECT. TRIATOM provides data necessary to drive ROTLEVD and DIPOLE. | ||

Restrictions:The size of matrix that can practically be diagonalised. TRIATOM allocates arrays dynamically at execution time and in the present version the total space available is a single parameter which can be reset as required. | ||

Unusual features:A user supplied subroutine containing the potential energy as an analytic function (optionally a Legendre polynomial expansion) is a program requirement. | ||

Running time:Case dependent but dominated by matrix diagonalisation. A problem with 600 basis functions (requiring 350000 words storage) takes 9 seconds on the CRAY XMP-48. |

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