Quantum mechanical calculation of diffusion of hydrogen isotopes in vanadium

- Diffusion of H isotopes in V was investigated with a quantum mechanical calculation.
- Calculated diffusion coefficients quantitatively agreed with the experimental data.
- H in V jumps via quantum mechanical tunneling between the two tetrahedral sites.
- H tunneling between ground states is dominant at low temperatures.
- H tunneling between exited states becomes important at higher temperatures.