Investigation of Unresolved hfs Splittings in theB2ΣState of CaCl with Use of rf-Pumped-Laser Double-Resonance Spectroscopy

Abstract

The hyperfine structure of the excited $B^2\Sigma$ state of Ca${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$ has been investigated with use of a novel technique that makes possible resolution of optically unresolved hfs components. The desired resolution is achieved through radio-frequency state labeling in a laser-rf double-resonance scheme. This procedure has completely resolved the four hfs components of $B^2\Sigma \leftrightarrow X^2\Sigma$ lines and placed an upper limit of 0.8 MHz on the $B^2\Sigma$ hyperfine structure.