ISOLATION OF STABLE INTERMEDIATES IN REACTIVE GAS-MIXTURES - ROTATIONAL SPECTRUM OF H3P...CL-2 IN A PULSED JET

The weakly bound dimer H3P ... Cl2 has been isolated in a pulsed jet by keeping the highly reactive components H3P and Cl2 separate until the point at which they expand into the evacuated Fabry-Perot cavity of a pulsed-nozzle Fourier-transform microwave spectrometer. The rotational spectra of the three symmetric-top isotopomers H3P ... Cl-35 CI-35, H3P ... CI-35 Cl-37, and H3P ... CI-37 Cl-35 detected in this way have been analyzed to give the ground-state spectroscopic constants B0, D(J), D(JK), chi1 (Cl), and chi2 (Cl) . Comparison of the dimer properties determined from the spectroscopic constants Of H3P ... Cl2 with those of the hydrogen-bonded dimer H3P ... HCI indicates that charge transfer is not predominant in the interaction of PH3 and Cl2. Some parallels in the properties of B ... Cl2 and B ... HCl are discussed for B=PH3 and HF.