Integrated Stokes Parameter Measurements of Zn Polarized-Electron Impact Excitation

Integrated Stokes parameter measurements of the fluorescence resulting from transversely-spin-polarized electron impact excitation of the Zn (4s5s)5$^{\mathrm{3}}$S$_{\mathrm{1}}$ state have been made. The atomic Zn target was produced by a Zn oven and a heated effusive channel that directed an atomic beam at right angles to both the fluorescence observation direction and the electron beam axis. In the cascade-free range of excitation between threshold of the (4s5s)5$^{\mathrm{3}}$S$_{\mathrm{1}}$ excitation and the first cascading (4s5p)5$^{\mathrm{3}}$P$_{\mathrm{J}}$ threshold, integrated Stokes measurements are consistent with theoretical predictions and inconsistent with other previously reported experimental results [1], [2]. The discrepancy between theory and the aforementioned previous experimental study motivated our investigation. Observed optical excitation functions are also reported and are in good agreement with other independent experimental measurements. [1] N. B. Clayburn and T. J. Gay, Phys. Rev. Lett. \textbf{119}, 093401 (2017). [2] L. Pravica et al., Phys. Rev. A \textbf{83}, 040701R (2011).