OBSERVATION OF ESR SPIN-FLIP SATELLITE LINES OF TRAPPED HYDROGEN-ATOMS IN SOLID H-2 AT 4.2-K

ESR spectra of H atoms, produced in γ-irradiated solid H2, were studied at 4.2 K. Two main lines of the ESR spectra of H atoms that are separated by about 500 G accompanied two weak satellite lines. Both satellite lines and main lines decrease with the same decay rate. In the D2-H2 mixtures, the satellite-line intensity depends upon the number of matrix protons. The spacing of the satellites from the main lines is equal to that of the NMR proton resonance frequency. It was concluded that the satellite lines were not ascribable to paired atoms but to spin flip lines due to an interaction of H atoms with matrix protons. The analysis of the spin flip lines and the main lines suggests that H atoms in solid H2 are trapped in the substitutional site. © 1990 American Chemical Society.