Collinear laser-ion beam determination of hfs in Cs II

By making use of the “velocity bunching” effect in collinear laser-ion beam spectroscopy, the hfs of the $\text{5}\text{p}{}^5{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{5}\text{d}\text{3}\text{2}\text{]}{}^0{}_2\text{→}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{6}\text{p}\text{3}\text{2}\text{]}{}_2$ transition in Cs II has been determined. A 30% reduction in linewidth compared with measurements using perpendicular laser-ion beam geometry is observed. The results for the $\text{6}\text{p}\text{3}\text{2}\text{]}{}_2$ level are compared with semi-empirical calculations.