The Molecular Structure of Arsine

Abstract

The method discussed by Nielsen for determining the rotational term values for the vibration states ν₃ and ν₄ has been applied to the spectrum of AsH₃ and by this means the Coriolis factor ζ₄^(z) has been determined. The value of ζ₂^(z) was known from an earlier work as was the value B^(xx). This permits the evaluation of B^(zz) when use is made of the zeta sum rule for pyramidal XY₃ molecules, i.e., ${\zeta }_2^{\mathrm{(z)}}{\mathrm{+\zeta }}_4^{\mathrm{(z)}}{\text{=(−1+(B}}^{\mathrm{(xx)}}{\text{/2B}}^{\mathrm{(zz)}})$ . These constants lead to values for the AsH distance r₀=1.523A and for the H–As–H angle α=91°34′.