AB-INITIO STUDIES ON THE STRUCTURE AND STABILITY OF P3H5

Ab initio studies applying the 3-21G, 6-31G, 6-31G and 6-31G** basis sets and also including MP2 corrections were carried out on four confo rmations of triphosphine. First, the geometry of the four molecules wa s optimized using the theoretical methods mentioned in the Hartree-Foc k (HF) scheme. The energies of the molecules at stationary points corr esponding to HF/6-31G* geometries were subsequently calculated includ ing electron correlation effects on the level of the second-order Moll er-Plesset (MP2) perturbation theory. Other physicochemical characteri stics of the hydrides, such as vibrational frequencies, dipole moments , net charges, and energies of the lowest unoccupied and highest occup ied molecular orbitals were obtained from theoretical calculations. Th e results of our ab initio calculations indicate that the gauche confo rmer between adjacent lone electron pairs and between P-H bonds with a djacent P-P bonds is the most stable conformer.