请问怎么找到各个分子的偶极矢量

yeahhanpei

一篇文中有这样的表述“To understand the orientation of AC molecules in the interfacial region, the orientation angle θ is defined as the angle formed between the AC dipole vector and the normal to the RDX crystal surface (i.e., the z-axis). The populations as a function of the AC centroid position projected to the z-axis and the cosine of the orientation angle q were calculated. ”
如上所述，要找到AC 分子的偶极矢量夹角与质心坐标的关系，我有两个问题:

1.在MS中怎么样才能找到AC分子的偶极矢量方向？
2.如何可以找到质心，对一个分子可以通过工具栏中的Centroid来找，但是因为此box中的AC分子比较多，一个一个的找很繁琐，想问下有木有简单的方法可以全部找出来？