Atomic hydrogen as spin probe in thermally and mechanically activated materials

Abstract

Atomic hydrogen H˙ could be stabilized at T  293 K in specially prepared fluoride and oxide compounds of aluminium: {AlF₃:OH} and {AlOOH_x}. The formation of atomic hydrogen was accomplished using irradiation including γ rays, X rays and UV radiation, and even sunlight, that is those wavelengths in the region of λ ⩽ 254 nm. The hyperfine coupling constant of H˙@AlF₃ could be precisely determined by using H˙@MeT₈ as a standard to calibrate the B₀ field. In the samples mentioned above H˙ acts a spin probe in two ways: (i) that it can be trapped in cages and stabilized with Pauli repulsion indicates sensitively and unambiguously that there are local host nano-cages present in the matrices and, moreover, (ii) that it acts as a spin probe for determining the matrix state of order with its spin dynamics as well as with the kinetic parameters of detrapping.