请教CRYSTAL17关于计算ECHG如何找坐标的问题？

zhuquexj

老师，这是CRYSTAL官网给出的计算ECHG的例子，但是对应上第5-7行坐标我不知道怎么去取，有知道的老师恳请赐教
ECHG                     # keyword
0                             #order of the derivatives: if not 0, the charge density gradients are computed
65                               #number of point along the B-A segment (see CRYSTAL User's Manual)
COORDINA            # cartesian coordinates of points A.B,C defining the window in a plane
-4.  -4.  0.0            #cartesian coordinates of point A (Angstrom)
4.  -4.  0.0           # cartesian coordinates of point B (Angstrom)
4.   4.  0.0            #cartesian coordinates of point C (Angstrom)
MARGINS           # margins are added to the window, in the order AB,CD,AD,BC
1.5 1.5 1.5 1.5           #width of the margins: in the order AB,CD,AD,BC
END         

guidofabris

Hello @zhuquexj

Those points could be, for example, the coordinates of the atoms that are inside the region that you want to draw the ECHG.

If you need a real example, just reply here that i help you out.