VIBRATIONAL RAMAN-SPECTRUM AND FORCE-CONSTANTS OF PHOSPHORUS, P4

From the most precise experimental measurements available from the gas phase for the three vibrational wavenumbers of P4, the primary stretching force constant f(r) = 2.06 mdyn angstrom-1 and two stretch-stretch interaction constants have been evaluated using a simple valence force field. The positive value of f(rr), and negative value of f(rr) are confirmed and the value of f(r) is found to be significantly smaller (15% and 7%, respectively) than the corresponding values calculated from the infrared spectra of solutions of phosphorus in carbon disulphide reported in the literature.