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 $0.7\pm 0.3$. 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.

Figure 1

Schematic of the collinear laser spectroscopy experimental setup. Ions were produced and accelerated to 15 keV, deflected 30${}^{\circ }$, and neutralized via charge exchange with a Na vapor. Laser light was co-propagated with the atomic beam and laser-induced fluorescence was collected by a reflector and detected by a photomultiplier tube. The dashed lines represent laser-induced fluorescence emitted from the atomic beam and reflected to the photomultiplier tube.

Figure 2

The charge-exchange processes between Na and Mn${}^{+}$ that were investigated in this work.

Figure 3

Partial energy-level diagram of Mn i relevant to the present work. Solid lines indicate laser excitations, and dashed lines represent the de-excitation pathways for fluorescence.

Figure 4

A typical ${}^{56}$Fe i spectrum is presented in the upper panel. Residuals from the symmetric and asymmetric Voigt function fits to the data are displayed in the bottom panel.

Figure 5

A laser-induced fluorescence spectrum of the ${}^6$$S_{5/2}{\to }^6$$P_{7/2}$ transition in Mn i is presented in the top panel. A schematic of all allowed HF transitions is shown in the bottom panel.

Figure 6

A laser-induced fluorescence spectrum of the ${}^8$$P$${}_{9/2}{\to }^8$$D$${}_{11/2}$ transition in Mn i is presented in the top panel. The spectrum contains two independent data sets over two frequency ranges that overlap at $-3000$ MHz. A schematic of all allowed HF transitions is shown in the bottom panel.

Figure 7

Normalized resonance signal $\zeta$ of the Mn i ground and metastable state transitions as a function of the MIVOC charge temperature.