Analytical potential energy function for tritium water molecule T2O((X)over-tilde1A1)

The greatest difficulty in deriving the analytical potential energy function of T2O((X) over tilde (1)A(1)) lies in Its identity with that of H2O((X) over tilde (1)A(1)) under the Born-Oppenheimer approximation. However, molecular potential energy function is actually a function of internal coordinates, such as bond length and bond angle which correlate with vibration energy, hence with vibration frequency, force constants and isotopic mass. Based on these relations, by using nuclear vibration, rotation, arid translation energies to correct electronic Energies, the force constants of T2O((X) over tilde (1)A(1)) can he obtained, which represent the difference in masses of isotopes H arid T. The Calculations are reasonably consistent with reference values. After determining the dissociation limits and dissociation energy and all parameters of two-body terms of T2O((X) over tilde (1)A(1)), the analytical potential energy function has finally been derived by using many-body expansion theory with due consideration of [tie isotopic effect. The potential energy contours correctly show the equilibrium structure of T2O((X) over tilde (1)A(1)) and the characteristics of the reactions T + OT -> T2O and O + T-2 -> T2O. The results lay a sound basis for further researches on reactive collisions.