TRIATOM - PROGRAMS FOR THE CALCULATION OF RO-VIBRATIONAL SPECTRA OF TRIATOMIC-MOLECULES

The TRIATOM program suite calculates energy levels, wavefunctions, and where appropriate, dipole transition moments and spectra, for rotatin g and vibrating triatomic molecules. Potential energy, and where neces sary, dipole surfaces must be provided. The programs use an ''act (wit hin the Born-Oppenheimer approximation) Hamiltonian, offer a choice of several body-fixed, internal coordinate systems based on two distance s and an included angle and employ basis function expansions of orthog onal polynomials. The calculations are variational, and rotational exc itation is treated using an efficient two-step algorithm. Constituent programs are TRIATOM which solves the vibrational problem and also per forms the first step for rotationally excited systems. SELECT which op tionally preselects basis functions for TRIATOM. ROTLEVD which perform s the second step for rotationally excited states. DIPOLE computes eit her line or band transition intensities. SPECTRA uses the data generat ed by the other programs to give simulated absorption or emission spec tra.