ENDOR study of a solitonic phase in a ?-irradiated single crystal of the malonic acid-urea 1: 1 adduct

A solitonic regime has been found in a y-irradiated single crystal of the malonic acid-urea 1: 1 adduct. The study has been performed on the ?-protons of the radicals by taking advantage of the high resolution of ENDOR spectroscopy and by a careful reproduction of the lineshapes. A solitonic density corresponding to 40 per cent of the radicals present in the single crystal has been obtained. The soliton can be equally ascribed to an incommensurate crystallographic phase or to a solitonic wave excited and sustained by a double-well hydrogen bond present in the crystal. The 1: 1 adduct seems to have a high electrical conductivity when measured in the crystallographic plane containing the adduct itself. © 1987 Taylor and Francis Ltd.