Barriers to Rotation and Inversion

摘要: Approximately two-thirds of the chapters in these two companion volumes are devoted to methods obtaining high-accuracy electronic wave functions for molecules and solids. The remaining third concerned with particular chemical species or properties, our chapter fits latter category. Within this category extensive literature on barriers offers special opportunities general interest theorists. First, it is possible make rather definitive statements quality required yield quantitative predictions. Second, analyzing ab initio ascertain physical origin barrier provide a quantum mechanically well-defined, but simple picture mechanism have been more extensively developed topic than any other.