应用多中心分区方法构建H_3分子反应势能面

Application of the Multi-Center Partition Method to Construct the Potential Energy Surface of H_3

势能面在分子反应动力学的研究中起着非常重要的作用.本文提出了一种新的势能面构建方法——多中心分区法.通过比较London-Eyring-Polanyi-Sato(LEPS)势能、多体展开势能、置换对称不变多项式三种方法,确定了H3分子的最佳势能函数表达形式,并应用准经典轨线方法分析了势能面的合理性,结果表明置换对称不变多项式能很好地描述H3分子的势能面特征.结合置换对称不变多项式和本文提出的多中心分区方法,可以有效改善H3分子势能面的精度并可能推广到高维反应势能面.

The potential energy surface plays an important role in studying molecular reaction dynamics. In this work, a new method, namely the ＂multi-center partition＂ method, is proposed to construct the potential energy surface of H3. The optimized function is first determined by comparing the London-Eyring-Polanyi-Sato（LEPS） potential, the many-body expansion potential, and the permutation-invariant polynomial potential. This comparison shows that the permutation-invariant polynomial fitting proposed by Bowman is the most efficient method for describing the topology of the H3 system. The quasi-classical trajectory method is used to analyze the rationality of those potential energy surfaces. By combining the multi-center partition method with the permutation-invariant polynomial method, the accuracy of the H3 molecular potential energy surface is greatly improved and could possibly be used in the fitting of potential energy surfaces in other systems.