Molecular-beam optical Stark and Zeeman study of theA2Π--X2Σ+(0,0) band system of BaF

Abstract

The $A{ }^{2}\ensuremath{\Pi}\ensuremath{-}X{ }^{2}{\ensuremath{\Sigma}}^{+}$ (0,0) band system of barium monofluoride (BaF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of static magnetic and electric fields. The field-free spectra for the $^{135}\mathrm{Ba}$F, $^{137}\mathrm{Ba}$F, and $^{138}\mathrm{Ba}$F isotopologues were modeled to generate an improved set of spectroscopic constants for the $A{ }^{2}$\ensuremath{\Pi}($\ensuremath{\upsilon}$ $=$ 0) and $X{ }^{2}$\ensuremath{\Sigma}${}^{+}$($\ensuremath{\upsilon}$ $=$ 0) states. The observed optical Stark shifts for the $^{138}\mathrm{Ba}$F isotopologue were analyzed to produce the permanent electric dipole moments of 1.50(2) and 1.31(2) D for the $A{ }^{2}$\ensuremath{\Pi}${}_{1/2}$($\ensuremath{\upsilon}$ $=$ 0) and $A{ }^{2}$\ensuremath{\Pi}${}_{3/2}$ ($\ensuremath{\upsilon}$ $=$ 0) states, respectively. The observed optical Zeeman shifts for the $^{138}\mathrm{Ba}$F isotopologue were analyzed to produce a set of magnetic $g$ factors for the $A{ }^{2}$\ensuremath{\Pi}($\ensuremath{\upsilon}$ $=$ 0) and $X{ }^{2}$\ensuremath{\Sigma}${}^{+}$($\ensuremath{\upsilon}$ $=$ 0) states.