Site Occupation and Local Vibration of Hydrogen Isotopes in Hexagonal Ti₅Si₃ H(D)_1−x

抄録

A structure analysis of Ti₅Si₃D_0.9 has been carried out to determine the deuterium trap sites by neutron powder diffraction with the Rietveld profile analysis. It is revealed that the deuterium atoms are located at octahedral (2b) sites surrounded by six Ti atoms in the crystal structure of Ti₅Si₃D_0.9, space group P6₃/mcm. Local vibration spectrum of hydrogen in Ti₅Si₃H_0.83 measured by neutron inelastic scattering supports this result; the energy eigenvalue of the primary vibration mode is found at 7.53 kJ/mol (78 meV). The hole radius and the spring constant of the Ti–H(D) bond are discussed.