Abstract: Mass spectrometry was used to measure appearance energies for the reaction RSS-t-Bu-RSS.+ t-Bu+ for R= Me, Et, i-Pr, and t-Bu. The data lead to the heats of formation of perthiyl radicals, RSS., and hence to SC bond dissociation energies in disulfides (ca. 54 kcal mol-') and to SS bond dissociation energies for the central bonds of tetrasulfides (32.3 f 1.0 kcal mol-'). The appearance energy method was also used to measure the ionization ...
