Structure of solvated electrons in 3-methylpentane glass. Second-moment electron spin resonance analysis of specifically deuterated 3-methylpentanes

Electron spin resonance spectra of γ-irradiation-produced solvated electrons at 77 K in the following specifically deuterated 3-methylpentane (3MP) glasses have been obtained: 3-methylpentane-d0, 3-methylpentane-3-d1, 3-methyl-d3-pentane, 3-methylpentane-2,2,4,4-d4, 3-methylpentane-1,1,1,5,5,5-d6, and 3-methylpentane-d14. A second-moment analysis of the spectral line shape has given the first detailed structural information about solvated electrons in alkanes. The electron interacts significantly with all the proton types in 3MP but most strongly with the terminal methyl groups assuming that the electron does not interact equally with the extreme ends of the same 3MP molecule. Then the most probable position of the solvated electron with respect to a first solvation shell 3MP molecule is in the carbon skeletal plane of 3MP on a line approximately perpendicular to the terminal carbon-carbon bond and passing through the terminal carbon. Each 3MP molecule has two possible orientations in this geometry which appear to be equally probable. The second-moment data together with previous electron spin-echo modulation data are compatible with three 3MP molecules in the first solvation shell and electron-to-first-solvation-shell-proton distances ranging from 0.35 to 0.43 nm