Analysis of isotope effect of hydrogen-absorbing Pd ultra-fine particle by X-ray powder diffraction and first principle multi-component MO calculation

• Published in: Chemical physics letters 2003-04, Vol.372 (3), p.503-507
• Main Authors: Ishimoto, T, Tachikawa, M, Yamauchi, M, Kitagawa, H, Tokiwa, H, Nagashima, U
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/S0009-2614(03)00414-7

The isotope effect for the geometrical and electronical relaxations of the hydrogen/deuterium-absorbing ultra-fine particles of Pd has been investigated using an X-ray powder diffraction, which shows that the bond distances of Pd n H are longer about 0.005 Å than those of Pd n D. Also, the first principle multi-component molecular orbital (MC_MO) calculation, which takes account of the quantum effect of proton/deuteron, has been employed for the optimization of Pd n H − and Pd n D − ( n=4,6). The H/D isotope effect of MC_MO calculation is good agreement with those of the X-ray powder diffraction and shows a little relaxation of the electronic charge densities.