Spectroscopic parameters of phosphine, PH3, in its ground vibrational state

- A combined fit of ground state rotational data was carried out.
- Improved spectroscopic parameters have been obtained.
- Predictions have been generated e.g. for planetary observations.

The ground state rotational spectrum of PH3 has been reanalyzed taking into account recently published very accurate data from sub-Doppler and conventional absorption spectroscopy measurements as well as previous data from the radio-frequency to the far-infrared regions. These data include ΔJ=ΔK=0 transitions between A1 and A2 levels, ΔJ=0, ΔK=3 transitions as well as regular ΔJ=1, ΔK=0 rotational transitions. Hyperfine splitting caused by the 31P and 1H nuclei has been considered, and the treatment of the A1/A2 splitting has been discussed briefly. Improved spectroscopic parameters have been obtained. Interestingly, the most pronounced effects occurred for the hyperfine parameters.