Accurate full-dimensional quantum state-resolved calculations studying reactions of methane currently rely on the multi-configurational time-dependent Hartree (MCTDH) approach and curvilinear coordinate systems. The coordinate systems used in MCTDH simulations of the reactive scattering of methane were based on a coordinate system and kinetic energy operator introduced by Evenhuis et al. (2007). In this coordinate system, the body-fixed frame is tied to the methyl fragment. Here it is shown that a revised definition of the methyl-fixed frame can reduce the correlation between the rotation of the methyl fragment and its internal motion. Furthermore, a new coordinate system which defines the body-fixed frame using the Jacobi vector associated with the dissociating bond and the symmetry axis of the methyl fragment is introduced. This coordinate system is designed for MCTDH simulations of the dissociative chemisorption of methane on surfaces.

研究甲烷反应的精确的全尺寸量子态解析计算目前依赖于多配置时变哈特里（MCTDH）方法和曲线坐标系。甲烷反应性散射的MCTDH模拟中使用的坐标系基于Evenhuis等人介绍的坐标系和动能算符。（2007）。在此坐标系中，身体固定的框架与甲基片段相连。此处显示了甲基固定框架的修订定义可以减少甲基片段的旋转与其内部运动之间的相关性。此外，引入了一种新的坐标系，该坐标系使用与解离键和甲基片段的对称轴相关的雅可比矢量来定义身体固定的框架。