Collinear laser spectroscopy on the ground state and an excited state in neutral 55 Mn

Collinear laser spectroscopy was performed on an atomic beam of stable ${}^{55}$Mn. An ion beam of ${}^{55}$Mn${}^{+}$ was generated in an ion source, accelerated to 15 keV, and neutralized via charge-exchange reactions with a Na vapor. A long-lived metastable state of Mn i, near-resonantly populated in the charge-exchange process, was investigated via laser probing in addition to a laser excitation from the ground state in Mn i. The relative population of the Mn i metastable state compared to that of the ground state was found to be $0.7\ifmmode\pm\else\textpm\fi{}0.3$. A theoretical calculation, which included feeding to the ground state and the metastable state from higher-energy excited electronic states populated in the charge-exchange process, agreed with the present result. The deduced $A$ and $B$ hyperfine coupling constants agreed with literature values, where available.