Measurement of the Relative Abundances and Recoil Energy Spectra of Fragment Ions Produced as the Initial Consequences of X-Ray Interaction with C2H5I, CH3CD2I, and Pb(CH3)4

Abstract

The fragment ions produced as the initial consequence of x irradiation of C₂H₅I, CH₃CD₂I, and Ph(CH₃)₄ have been measured with a specially designed mass spectrometer for their relative abundances and kinetic‐energy spectra. The x rays used in this experiment should in the case of iodine‐containing molecules give rise to photoionization primarily in the $L$ shell, and in the case of lead, the $M$ or $L$ shells. As in the earlier studies on CH₃I, the molecules decomposed nearly completely into their constituent elements as the result of the high degree of ionization resulting from the reorganization of the heavy atoms to an inner‐shell vacancy by means of Auger processes. Calculations based on the Coulombic repulsion of point charges are compared with the experimentally determined recoil energies. The agreement is reasonable, although the experimental values are generally lower than the calculated ones. The relative recoil energies of H⁺ and D⁺ from the study on deuterated ethyl iodide suggest that the $\beta$ carbon on the average loses as many electrons as the carbon next to the iodine; while the low recoil energy of Pb suggests that the decomposition of highly charged tetramethyl lead is essentially symmetrical.