M^|^ouml;ssbauer Study of Iron Iodide Produced by a Reaction of Laser-Evaporated Iron Atoms and Methyl Iodide

Abstract

Laser-evaporated iron atoms have high-energy and thus can react with a variety of molecules to produce novel species. These kinds of novel species are generally unstable and can only be trapped in low-temperature matrices. The author has previously reported the production of a variety of novel iron oxide and iron nitride species by reactions of laser-evaporated iron atoms with oxygen 1 and nitrogen. 2 We have also reported a study into the reaction of laser-evaporated iron atoms with SF6 gas, in which FeF3, Fe2F6, and Fe2F4 were investigated. 3 Mossbauer spectra provide direct information of the electronic properties of novel iron species that are trapped in low-temperature matrices, from which the structures of the species are derived with the assistance of molecular orbital calculations. In the case of halide species, the isomer shift δ and quadrupole splitting ∆ EQ are strongly influenced by the number of halide atoms and structure of a molecule. In this study, we investigate the novel iron iodide products of the reaction of laserevaporated iron atoms with methyl iodide CH3I. The photochemistry of CH3I itself has been studied extensively, and it has been reported that the photolysis of CH 3I produces a methyl radical and an iodine atom. 4 Laser-evaporated iron atoms may break CH3I molecules and release iodine atoms for the production of iron iodide species. The vaporization of solid FeI 2 produces the monomer as the major species while the dimeric species was found as a minor species. The vapor pressures of the two species have been measured and the standard sublimation enthalpy has been reported. 5 Although the infrared spectra of gaseous FeI 2 has been reported, 6 the