Mass spectra of some deuterated ethanes. II. An empirical method of calculation of the spectra

Abstract

Relative intensities of the C2 fragment ions in deuterated (d1–d5) ethanes have been calculated on a statistical basis from the mass spectrum of C2H6 and have been compared with experimental mass spectra previously reported in Part I. For these calculations we have introduced a correction for the relative probabilities of loss of two hydrogen atoms in addition to weighting factors for the loss of H and D atoms. The isotopic weighting factors have been expressed in terms of power series. By this means satisfactory agreement was obtained between the calculated and experimental mass spectra.This treatment also made it possible to calculate the intensities of doubly charged C2 fragments that appear in the C1 mass spectra. We then estimated the degree of reshuffling of hydrogen atoms prior to C—C bond rupture and obtained calculated mass spectra that were in reasonable agreement with the experimental data for the C1 region of the mass spectrum.Experimental mass spectra have been newly obtained for 1,1-d2 ethane and 1,1,1,2-d4 ethane and are included here for completeness.