CALCULATED AND MEASURED DOUBLE-IONIZATION ENERGIES OF CH3BR, CH2BR2 AND CHBR3 TO SINGLET AND TRIPLET ELECTRONIC STATES OF THEIR DICATIONS

Double-ionization energies of CH3Br, CH2Br2 and CHBr3 to singlet and t riplet electronic states of their dications were calculated and measur ed. Double-charge-transfer spectroscopy was employed in the experiment al part of the study; the computational work was carried out using a s emi-empirical form of the multiple-scattering X alpha method. For CH3B r, each spectral peak could be identified with a calculated double-ion ization energy thus giving a clear insight into the electronic transit ions which give rise to the spectra, The predicted densities of states for CH2Br22+ and CHBr32+ were, however, much higher than that for CH3 Br2+, so that groupings of states had to be established to correlate w ith the information obtained from some peaks of the spectra. (C) 1998 John Whey & Sons, Ltd.