Knowledge Bank

Sideband-OODR-Zeeman (SOODRZ) spectroscopy is not only a powerful tool for characterizing the electronic structure of diatomic molecules by use of the Zeeman effect, but it is also a high-resolution spectroscopic probe for examining molecular fine structure. By using an electro-optic (EO), rather than an acousto-optic modulator, the sensitivity of the sideband technique can be improved by at least a factor of ten, and consequently, very small Zeeman splittings ( 5 MHz) can be resolved. EO-SOODRZ results for several transition metal hydrides, including NiH and PtH, where we have been able to resolve extremely small ($\sim$5 G) ground and excited state proton hyperfine splittings will be presented. The ability to use EO-SOODRZ spectroscopy to systematically step through a complicated, congested sequence of lines to measure Zeeman tuning coefficients of individual transitions comprising the composite feature will also be demonstrated. Finally, we will also discuss progress made in understanding and optimizing the sideband technique, including the effect of various detection schemes and modulation conditions on the SOODRZ lineshape. The simplest possible form of the SOODRZ lineshape was determined to be a second derivative of a Lorentzian.