FOURIER TRANSFORM SPECTRA OF THE $A^{2}\Pi - X^{2}\Sigma^{+}$ TRANSITION OF MgBr NEAR 380 NM

Author Institution: Centre of Molecular Beam and Laser Chemistry, Department of Chemistry, University of WaterlooIt is well-known that the $A^{2}\Pi$ state of the magnesium monohalide radicals $(MgX, X=F, Cl, Br, I)$ are predissociated. Spectroscopic results of this predissociation are available, however, only for MgF and MgCl. In this study, the high-resolution emission spectra of the gascous magnesium bromide (MgBr) radical have been detected. The spectra of MgBr were recorded by using Bruker IFS120HR Fourier transform spectrometer, modified to record double-sided interferograms. The MgBr radical was generated in the microwave discharge of Ar buffer gas (1.5 Torr) with a trace of the vaporized $MgBr_{2}$ salt. The vapor of the $MgBr_{2}$ salt was obtained in a quartz tube heated to about $400^{\circ}C$ with a heating tape. The (0,0) and (1,1) vibrational bands for the $A^{2}II_{1/2} - X^{2}\Sigma^{+}$ were clearly identified near 380 nm, but only the (0,0) sub-band for the $A^{2}II_{3/2} - X^{2}\Sigma^{-}$ was detected, probably due to a predissociation. The assignment is in progress