中文摘要：

获得T2O（X↑1A1）解析势能函数的主要困难在于Born-Oppenheimer近似下T2O（X↑1A1）与H2O（X↑1A1）势能函数的不可区分性.然而,在Born-Oppenheimer近似下,分子势能函数实际上是键长、键角这些内坐标的函数,内坐标与核的运动相关,因而与分子振动频率、力常数和同位素质量有关.基于这种关系,用核运动效应对Born-Oppenheimer近似下T2O（X↑1A1）的电子能量进行修正,可获得体现同位素氢和氚质量差异的力常数,其结果与有关文献值是相符的.然后用多体项展式理论和方法,并考虑T2O（X↑1A1）中两体项中的同位素效应,在确定T2O（X↑1A1）离解极限和离解能以及计算所有两体项参数的基础上,获得了T2O（X↑1A1）的解析势能函数.对应的等值势能图正确反映了T2O（X↑1A1）的平衡结构特征,以及T＋OT→T2O和O＋T2→T2O的反应特点,为后续的碰撞研究提供了条件.

英文摘要：

The greatest difficulty in deriving the analytical potential energy function of T2O（X↑1A1） lies in its identity with that of H2O（X↑1A1） 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,and translation energies to correct electronic energies,the force constants of T2O（X↑1A1） can be obtained,which represent the difference in masses of isotopes H and 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↑1A1）,the analytical potential energy function has finally been derived by using many-body expansion theory with due consideration of the isotopic effect.The potential energy contours correctly show the equilibrium structure of T2O（X↑1A1） and the characteristics of the reactions T＋OT→T2O and O＋T2→T2O.The results lay a sound basis for further researches on reactive collisions.