IDENTIFICATION OF THE ELECTRONIC-TRANSITIONS IN THE DOUBLE-IONIZATIONOF 6 AMINES TO SINGLET ELECTRONIC STATES OF THEIR DICATIONS

The double-ionization energies of methylamine, dimethylamine, trimethy lamine, ethylamine, propylamine and butylamine were measured and calcu lated. Transitions to singlet states of the ions were considered in or der to complement the previously obtained information on transitions t o triplet states. The double-ionization energies were determined exper imentally from the positions of peaks observed in double-charge-transf er spectra. Information on the electronic transitions giving rise to t he peaks was obtained by comparing the measured energies with those ca lculated using a semi-empirical form of the multiple-scattering X alph a computational method. It was shown that for some of the dications th e density of states is high. An ab-initio computational method, used w ith the 3-21G and 6-31G basis sets, predicted quite accurately the tr end in the lowest double-ionization energies measured. (C) 1997 Elsevi er Science B.V.