ESR OF POLYCRYSTALLINE V2O5 TREATED WITH H-ATOMS AT ROOM-TEMPERATURE

Room temperature treatment of polycrystalline V205 with H atoms from a microwave discharge results in an immediate formation of a V4+ signal. At 77 the ESR line is of Gaussian type and shows a 29-line hyperfine pattern centred around g|| = 1.915 ( A|| = 43 G). At room temperature the signal becomes Lorentzian and structureless, indicating that the hopping frequency of the unpaired electrons exceeds the hyperfine coupling constant expressed in frequency units. The spectrum is interpreted as originating from an electron interacting with four equivalent vanadium nuclei. The possible site of hydrogen trapping within the V2O5 lattice is presented. © by R. Oldenbourg Verlag