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[交流] 【求助】关于分子动力学模拟中系统大小选取的问题

在GULP教程中有这样一句话，我理解不了，还请各位帮忙解释一下说的是什么意思，看文中的似乎是不能只取原胞，这是很容易理解的，也是肯定不能选那么小的，但是到底分子动力学模拟中系统大小应该如何选取呢，还有哪些因素需要考虑到呢，和声子的 k=(0,0,0) 又有什么关系呢？
The other key issue is the size of the system to be simulated. A lot of systems can be
described by a primitive cell (the assymetric unit). However, running MD on this cell
would be meaningless - every cell of the crystal would be moving perfectly in phase
which is not physical. In fact, using a single unit cell is just the same as sampling the
phonons at just the k=(0,0,0) point - this is the point at which all cells are in phase.
感觉这个问题似乎不是只针对GULP才有的，是所有做分子动力学模拟都需要考虑的问题，所以放在这个版块里，还希望各位大侠可以多指教。

[ Last edited by ghcacj on 2010-12-20 at 15:46 ]

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