Far-infrared laser magnetic resonance spectra of the PH and PD radicals in X3Σ −

Abstract

Far-infrared laser magnetic resonance (LMR) spectra of PD in the ground vibronic state ( X 3Σ −, v = 0) were observed using the 570.6-, 380.6-, 287.3-, 232.9-, 191.6-, and 164.6-μm laser lines as sources, and the v = 1 spectrum was also observed with the 392.1-μm laser line. By combining the present results with mid-infrared LMR and optical spectroscopic data already reported, the molecular constants of PD in X 3Σ − were refined as follows: B 0 = 4.362 8675(77), D 0 = 0.000 118 03(24), λ 0 = 2.208 48(57), γ 0 = −0.039 900(34), B 1 = 4.269 248(65), λ 1 = 2.209 5(10), γ 1 = −0.038 82(21), and ν 0 = 1653.284 91(51), all in cm −1 with 3σ in parentheses. The 31P hyperfine coupling constants were determined to be α P = 0.004 330(39) and β P = −0.005 312(32) for the v = 0 state and α P = 0.004 66(40) and β P = −0.004 79(69) for the v = 1 state, again in cm −1 with 3σ in parentheses. The far-infrared LMR spectra of PH in the X 3Σ −, v = 0 state were measured on five new laser lines, and an analysis of the observed spectrum combined with that already reported yielded molecular constants much improved in precision. Using the results on both PD and PH, the equilibrium structure and the potential constants up to the fourth order were derived, where allowance was made for adiabatic and nonadiabatic corrections: r e BO = 1.42140(22) A ̊ , ω e (PH) = 2366.79(16) cm −1, a 1 = −2.3797(18), and a 2 = 3.461(14).