Abstract
Fragment ions with excess-kinetic-energy(KE ion)are formed mainly from direct cleavage of highly excited parent molecules. Therefore masss pectrum of KE ions(KE mass spectrum)corresponds well to the structure of a compound. KE mass spectra of about 130 kinds of compounds have been treated with an electric computer system. The characteristic peaks and peak groups(named Key Mass)which indicate the presence and/or absence of some fragment group(substructure, e.g. -CH2OH, -C2H5, CH3CO-)were selected by judging from the relative intensities of various ion peaks related various substructures. The relative intensities of Key Mass(named Key Mass Value)of a sample compound are compared with their standard values calculated above. Further treatments of these values have been done to obtain the final information about a substructure. It indicates the usefulness of KE mass spectrum for computer identificatlon.