Hyperfine Structure of the 3p44s 4p State of the Chlorine Atom

This work followed upon preceding work^{1, 2, 3} devoted to calculations ab-initio of hyperfine constants of certain atomic states of nitrogen and fluorine. The interest caused by these elements was due to experimental work of spectroscopy to very high resolution completed by the same laboratory and measuring hyperfine spectra several elements of which nitrogen, fluorine, oxygen and chlorine^{4, 5, 6, 7}. The multi-configuration nonrelativistic Hartree-Fock method combined with the approximation of Breit-Pauli⁸ to take account of the relativistic effects was used successfully in calculation of the hyperfine constants. This same method was also employed successfully in the hyperfine structural analysis of the fundamental state of chlorine⁹. We use it in this work to calculate the hyperfine structures of the excited state 3p⁴ 4s ⁴ P of the atom of chlorine.