The Fundamental Absorption Bands in the Infrared Spectrum of Phosphine

The four fundamental bands in the infrared spectrum of PH3 have been analyzed. The bands ν1 and ν3 yield values of B(xx) and [(1—ζ2(z))B(zz)—B (xx)] as well as values for the centers of the bands. The method of Nielsen for arriving at explicit expressions for the rotation term values of ν2 and ν4 has permitted the evaluation also of the quantity (1—ζ4(z))B(zz) and to infer the centers of these bands. The structure of the molecule has been derived from this information and the zeta sums. The PH distance r0 obtained is equal to 1.42A, and the H–P–H angle is equal to 93° 50′.