Gas-Phase Electron Resonance Spectra of Fluorine and Chlorine Atoms in Their Ground (P322) and Excited (2P½) Electronic States

The gas‐phase electron resonance spectra of fluorine and chlorine atoms in their ground (${}^2{P}_{\frac{3}{2}}$ ) and excited (²P_½) states are described. Fluorine atoms are formed by passing CF₄ through a microwave discharge; the ${}^2{P}_{\frac{3}{2}}$ spectrum shows six strong lines and five weaker lines, three of the latter being previously unreported and arising from ΔM_F=0 transitions. Two lines of the ²P_½ spectrum are detected and their intensity relative to that of the ground‐state spectrum indicates a non‐Boltzmann distribution between the ${}^2{P}_{\frac{3}{2}}$ and ²P_½ states. Chlorine atoms are formed by passing CF₃Cl or CF₃Cl/Cl₂ mixtures through a microwave discharge. In addition to the intense ³⁵Cl and ³⁷Cl ${}^2{P}_{\frac{3}{2}}$ spectra, four weak lines arising from excited ³⁵Cl ²P_½ atoms are detected. The intensities of these lines also indicate a non‐Boltzmann distribution between the ground and excited states.