Accurate Quantum Chemistry for Space and Ultimate Science

氢团簇及其相关化合物是空间化学中的关键分子。然而，由于轻氢的存在，原子核运动的量子效应是不可忽视的，在这些系统中，非玻恩-奥本海默(Non-BO)计算应该是非常重要的。我们将薛定谔方程的求解方法推广到非BO计算，特别是以氢分子离子为靶，精确描述了电子激发态、振动激发态和转动激发态。我们还提出了从非BO波函数中获得势能曲线的分析方法。我们还在BO近似下对几个氢团簇进行了非常精确的计算。本研究可以为空间化学建立一种新的基础理论方法作为探索性研究，并在不久的将来将其应用于更复杂的氢相关化合物，探索空间分子的演化过程。

Hydrogen clusters and its relative compounds are well known as the key molecules in space chemistry. Due to light hydrogen, however, the quantum effect of the nuclear motion cannot be ignored and the non-Born-Oppenheimer (non-BO) calculation should be essentially important in these systems. We extended the method for solving the Schroedinger equations to the non-BO calculations especially for accurately describing the electronic, vibrational, and rotational excited states, using hydrogen molecular ion as a target. We also proposed the analysis method to obtain the potential curve from the non-BO wave function. We also performed the very accurate calculations of the several hydrogen clusters on the BO approximation. The present study could establish a new basic theoretical method for space chemistry as an exploratory research and we will apply it to more complex hydrogen related compounds in near future to explore molecular evolution process in space.