Zeeman-tuned rotational level-crossing spectroscopy in a diatomic free radical

摘要

Rotational levels of molecular free radicals can be tuned to degeneracy usinglaboratory-scale magnetic fields. Because of their intrinsically narrow width,these level crossings of opposite-parity states have been proposed for use inthe study of parity-violating interactions and other applications. Weexperimentally study a typical manifestation of this system using $^{138}$BaF.Using a Stark-mixing method for detection, we demonstrate level-crossingsignals with spectral width as small as 6 kHz. We use our data to verify thepredicted lineshapes, transition dipole moments, and Stark shifts, and toprecisely determine molecular magnetic g-factors. Our results constitute aninitial proof-of-concept for use of this system to study nuclear spin-dependentparity violating effects.