Mass Spectrometric Study of CH3D. Dissociation Probabilities of C–H and C–D Bonds by Electron Impact

Abstract

A pure sample of CH₃D has been prepared and studied in the mass spectrometer. The mass spectrum of CH₃D cannot be predicted from that of CH₄ by assuming complete similarity between H and D (except mass). More information has been obtained on the difference in behavior of H and D on electron impact previously noticed by Delfosse and Hipple for C₂H₂D₂. There is a difference in dissociation probability of C–H and C–D bonds which is approximately constant for several ionization processes and over a considerable range in electron energy. In addition to this there is a difference in behavior of H atoms in CH₄ and H atoms in CH₃D. In order to account for the mass spectrum of CH₃D in terms of the mass spectrum of CH₄ both these effects must be taken into consideration. Re‐examination of the data of Delfosse and Hipple points not only to the difference between H and D atoms in C₂H₂D₂, but also to a difference in behavior of H atoms in C₂H₄ and H atoms in C₂H₂D₂.