Size evolution potential energy surfaces

In contrast with grid-based methods, there is no need to first build analytical models for the potential energy surface, which makes Gaussian-based methods easier to use. In addition, an approximate description based on a limited number of quantum trajectories can provide a more intuitive interpretation of the reaction mechanism than the evolution of a wavepacket on a grid. However, increasing the size and complexity of the system may require an even more approximate description such as semi-classical trajectories presented below. 

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