Linestrengths of phosphorus monohydride: II. Isotope effect in the PX (X=H, D) b 1Σ+ (v′=0) → X 3Σ− (v″=0) emission Original Research Article

The linestrength of OP and SR branches of the PD (b 1Σ+(v′=0) → X 3Σ−(v″=0)) spin forbidden transition, and the ratio μ‖/μ⊥ of transition moment components, are obtained by emission intensities in a microwave afterglow apparatus. Results from similar experiments on PH are also reported. A discussion by the point of view of isotope substitution leads to following conclusions: (1) the difference in μ‖/μ⊥ ratio, of about 13% for systems under study, is attributed to the perpendicular component μ⊥ as essentially the one affected by center of mass shift; and (2) discrepancies in the correlation of branches are plainly due to a different balance between spin–orbit and spin–rotation energy terms.