Gas-phase EPR linewidths and intermolecular potentials. II. Experimental results for the F–He–F2 system

Detailed experimental results are reported for F‐atom EPR linewidths in both the ²P_3/2 and ²P_1/2 states in the presence of the perturbing species He, F₂, and F atoms. Line broadening cross sections for He and F₂ show similar features. The ²P_3/2 EPR transitions involving a Zeeman level with projection quantum number of absolute value 3/2 have larger cross sections than ones involving only 1/2 levels. However, both the ratio and magnitude differ between He and F₂. For both F₂ and He, ²P_1/2 cross sections are in the range 50–100 times smaller. On the other hand F‐atom perturber cross sections all are about equal in the ²P_3/2 state and only slightly larger than the cross section in the ²P_1/2 state. The $\mathrm{He–F}$ cross sections are subjected to detailed comparison with the theory of the preceding paper, with the conclusion that the model second‐order dipole‐dipole potential does an excellent qualitative job of predicting the observed cross sections, though quantitative discrepancies are noted. Possible explanations for these discrepancies are advanced. Likewise qualitative explanations are set forth to explain the F₂ and F‐atom cross sections. It is speculated that additional theoretical and experimental work may demonstrate that EPR line broadening cross sections are effective probes of both long‐ and short‐range potentials.