THE OPTICAL STARK SPECTRUM OF THE $A^{3}$$\Phi_{4}-X^{3}\Phi_{4}$ BAND SYSTEM OF IRIDIUM MONOFLUORIDE, IrF

Author Institution: Department of Chemistry and Biochemistry, Arizona State University, Tempe,AZ 85287; Center for Lasers, Atomic and Molecular Sciences and Physics Department, University of New Brunswick, Fredericton, NB Canada E3B 5A3Recently the New Brunswick group {\textbf{87}} 557, 2009.} reported on the field-free detection and analysis of the $A^{3}$$\Phi_{4}-X^{3}\Phi_{4}$ band system of IrF. Here we report on the analysis Q(4)(15922 cm$^{-1}$) branch feature of the (1,0) band of the $^{191}$IrF isotopologue of that system recorded at field strengths of up to 3000 V/cm. The spectra are surprisingly complex at the achieved resolution of 40 MHz due to the presence of both the $^{191}$Ir(I=3/2) and $^{19}$F(I=1/2) magnetic hyperfine splitting. The determined permanent electric dipole moment, $\mu_{el}$, for the $X^{3}\Phi_{4}$ state is compared with that recently determined {\textbf{131}} 114315, 2009.} for the $X^{3}\Phi_{4}$ state of isovalent CoF. The trend in $\mu_{el}$ amongst the ground states of IrF, IrC and IrN {\textbf{104}} 8183, 1996.}will be discussed. Finally, a simple molecular orbital correlation diagram will be used to rationalize the change in $\mu_{el}$ upon excitation from the $X^{3}\Phi_{4}$ to $A^{3}\Phi_{4}$ state