Threshold Photoelectron-Photoion Coincidence Spectroscopy: Dissociation of the 1-Chloroadamantane Ion and the Heat of Formation of the 1-Adamantyl Cation

摘要

Threshold photoelectron-photoion coincidence spectroscopy was used to investigate the dissociation of the 1-chloroadamantane ion (C_(10)H_(15)Cl~+). The product of Cl loss reaction, 1-C_(10)H_(15)~+, was the only fragment ion at experimental photon energies below 13.0 eV. Through the simulation of the metastable time-of-flight distributions of the 1-C_(10)H_(15)~+ ion and the breakdown diagram, the 0 K appearance energy of 1-C_(10)H_(15)~+ was determined to be 10.10 ± 0.02 eV. Using this result and the IE value of 1-C_(10)H_(15)Cl, 9.30 ± 0.10 eV, the dissociation energy of the Cl loss reaction was determined to be 0.80 ± 0.10 eV. Using the known heats of formation of C_(10)H_(15)Cl and Cl, the 298 and 0 K heats of formation of the 1-C_(10)H_(15)~+ ion were obtained to be 679.2 ± 3.2 and 731.9 ± 3.2 kJ/mol, respectively.