The first spectroscopic evidence for the existence of the HBX and DBX (X = F, Cl, Br) free radicals has been obtained from laser-induced fluorescence and wavelength-resolved emission spectra. The vibrational frequencies measured in emission are in excellent agreement with our ab initio (CCSD(T)/aug-cc-pVTZ) predictions. The patterns of resolved rotational sub-band structure and deuterium isotope effects have been used to positively identify the radicals. The experimental data and ab initio predictions will be useful in searches for the matrix infrared and microwave spectra of these new radicals. Copyright
The reactive species BBr was produced by the glow discharge of the BBr3 vapor in a free space cell. Rotational spectra of the four isotopic species were observed between 117 and 480 GHz. For lower rotational transitions the hyperfine structure