SUBSTITUENT EFFECTS IN MASS SPECTROMETRY . MASS SPECTRA OF SUBSTITUTED PHENYL BENZYL ETHERS

From a consideration of smoothed energy distributions, ionization potentials, andappearance potentials, the effect of substituents on the ratio of molecular ion to total daughter ion abundance in the mass spectra of substituted phenyl benzyl ethers (XC6H4OCH6C6H5) has been calculated. The results show a qualitative agreement with experiment in 20-eV spectra, but for some substituents (e.g., W-CH3O, m-OH, and m-NH2), the observed molecular ion abundance is much greater than the calculated value. In these cases it may be that the assumed energy distributions are a poor approximation to those actually occurring and/or isolated electronic states of the molecular ions may be generated upon electron impact. © 1969, American Chemical Society. All rights reserved.