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

Abstract

The linestrength of O P and S R branches of the PD ( b 1 Σ +(v′=0) → X 3 Σ −(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.