Laser-induced Fluorescence Spectrum of PH₂ Cooled in a Supersonic Jet

Laser-induced fluorescence spectrum of gas-phase PH₂ cooled in a supersonic jet has been observed in the range of 490-550nm. The rotational analysis has been carried out for the （0,0,0）←（0,0,0）,（0,1,0）←（0,0,0） and （0,2,0）←（0,0,0） bands of the A²A₁←X²B₁ electric transition of PH₂.Approximately 220 lines have been assigned including 52 lines which are assigned for the first time. From the rotational structure of the spectrum, we obtained all molecular constants of PH₂ in which ε_bb and ε_cc are new data. Finally, we discussed the rotational perturbations which exits in the electronically excited state.