H₂-broadening coefficients in the ν₂ and ν₄ bands of PH₃

H-broadening coefficients are measured for 41 transitions of PH in the R branch of the ν band and the P, P, and Q branches of the ν band, using a tunable diode-laser spectrometer. The recorded lines with J values ranging from 2 to 16 and K from 0 to 11 are located between 995 and 1106 cm. The collisional widths are determined by fitting each spectral line with a Voigt profile, a Rautian profile, and a speed-dependent Rautian profile. The latter model provides larger broadening coefficients than the Voigt model. These coefficients γ(J,K) are found to decrease slightly on the whole as J increases and they decrease significantly for K values approaching or equal to J (J≥4). The H-broadenings are also calculated on the basis of a semiclassical model of interacting linear molecules, using an atom-atom Lennard-Jones potential in addition to the weak electrostatic contributions. The theoretical results are in satisfactory agreement with the experimental data and reproduce the J and K dependencies of the broadenings, but the decrease observed for the R(J,K) transitions with K=J is notably overestimated.