用解析函数拟合NH3复合分子中质子转移势能的理论研究

采用量子化学abinitio(4-31G基组)方法，计算了NH3复合分子(H3N…H^+…NH3)中的质子转移势能，氢键长度和取向的变化都没有影响它的双势阱特征，长度越长、分子主轴偏离氢键键轴越大，双势阱间能垒越高。采用最小二乘法拟合上述abinitio计算结构，找到了理想的解析函数，从而扩大其适用范围。针对体系的对称性和非对称性，我们改进了Φ4函数和Morse函数，从而使拟合结果得到了明显提高，拟合相关系数最高达0.999。

Theory study on the analytic functions fit to proton transfer potentials in ammonia complex

Proton transfer potentials in ammonia complex H3N…H^+…NH3 are calculated by using the quantum chemical ab initio method (4-31G basis set). It shows that the variations of H-bond length and its orientation make no impact on the characteristics of double potential well. The longer H-bond length and the more heavily the molecular main axle deviated from H-bood axle, the higher the energy barrier between double potential wells. Suitable analytic functions can be found with least square fitting to the ab initio results so as to extend the analytic functions' usage range. Considering the system's symmetry and unsymmetry, we modify Φ4 functions. So the simulation results are noticeably improved, and the highest fitting correlation coefficient can reach 0.999.