Abstract

PH3 absorbs in the 5- and 8-μm window regions of the atmospheres of Jupiter and Saturn. In particular, in the 2000-2500- cm⁻¹ region the ν₁, ν₃, 2ν₂, 2ν₄, and ν₂ + ν₄ bands overlap. This overlap and the strong Coriolis interactions and Fermi resonance make the analysis difficult. However, low temperatures eliminate high J lines from the spectra, thus simplifying them, as well as providing spectra which imitate actual planetry conditions. Using a nonlinear least-squares technique we obtained broadening coefficients for the cases of PH₃ + PH₃ and of PH₃ + He at room temperature. Data reduction and more experimental work at lower temperatures, down to 140 K, are in progress. The spectra were obtained by means of a high resolution Fourier transform spectrometer (0.006-cm⁻¹ resolution) using absorption cells of 5- and 57mm length and different pressure conditions. For the self-broadening case we found broadening coefficients that are ~10% lower than values previously reported for the microwave region.

© 1989 Optical Society of America