Abstract
Mass spectra of excess-kinetic-energy ions(KE ions)formed under electron impact have been studied by using a commercial mass spectrometer with the modified ion source. Parent ions of KE ions may be so much excited than those of thermal-energy ions that they may decompose more quickly and give much simple cleavage ions and less rearrangement ions. Therefore the mass spectrum of KE ions must be different from the ordinary mass spectrum. Several compounds of alcohols and ethers have been studied. Simple relations have been found between the mass spectra of KE ions and the structure of these compounds. Generally, fragment ions which are smaller than a half of a molecule can be observed as KE ions and the terminal groups of a compound, such as CH3CO, -CH2OH, HCO-, C2H5-and so on, give the intense peaks. It has been proved that the mass spectra of KE ions show less rearrangement and are useful for the structure determination of organic compounds
