T. HIRAO AND P. F. BERNATH, Centre of Molecular Beam and Laser Chemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
It is well-known that the A 2 state of the magnesium monohalide
radicals (Mg X, 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 gaseous 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 MgBr2 salt. The vapor of the MgBr2 salt was obtained in a quartz tube heated to about 400oC with a heating tape. The (0,0) and (1,1) vibrational bands
for the A 2 1/2 - X 2 + were clearly identified
near 380 nm, but only the (0,0) sub-band for the A 2 3/2 - X 2 + was detected, probably due to a predissociation. The assignment is in progress.