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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.43 [2005] >
IJPAP Vol.43(07) [July 2005] >
| Title: | Hydrogen diffusion in Fe0.5Ti0.5—Quantum isotope effect |
| Authors: | Gibson, M Stalin Mano
Lawrence, N |
| Keywords: | Hydrogen diffusion
Activation energy
Quantum isotope effect
Barrier energy
Intermetallic compound |
| Issue Date: | Jul-2005 |
| Publisher: | CSIR |
| IPC Code: | C01B 4/00 |
| Abstract: | A quantum mechanical
theory has been used to workout the Quantum Isotope Effect (QIE) on activation
energy of the intermetallic compound Fe0.5Ti0.5. The QIE
has been calculated with the assumption that the hydrogen isotopes move as ions
which diffuse interstitially in the crystal potential computed with the
screened Coulomb interaction between proton and host ions. The QIE arises from
the quantum mechanical zero point energy associated with the confining potential
at the saddle point in the interstitial channel. In Fe0.5Ti0.5
system, the inequality Ea,H > Ea,2H > E a,3H in activation energy
is reversed. QIE values have been calculated for various pressures ranging from
normal to 2.5 GPa. A remarkable agreement between theory and experiment is
observed. The value of QIE slightly increases with pressure. In this compound,
hydrogen prefers the octahedral position and diffuses by O – O jump mechanism. |
| Page(s): | 532-534 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.43(07) [July 2005]
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