软件版本为AMS2019.3及之前的版本，AMS2020以后的版本请参考链接：Constrained DFT（CDFT）方法限制局部带电

以如下两个分子之间相互作用为例，其中$CO_2$带-1电荷，大分子带+1电荷，总体为中性。当然其他带电情况也是可以的，但是CDFT相关设置目前只允许设置一个限制条件。本例中，总电荷在Main中设置完毕，对$CO_2$带电条件的设置在CDFT面板完成。

Main面板一般性参数设置，包括总电荷、基组、泛函等，需要注意的是，因为两个片段实际都是开壳层因此选择了Unrestricted方法。基组需要选择Core None，因为本方法不支持Frozen core。

设置分区：

选择限制条件为charge，表示只限制电荷，当然选择charge and spin同时限制电荷、自旋。并设置某个分区的电荷，本例设置$CO_2$电荷量为-1

计算过程，我们可以看到logfile中，存在两个片段之间的自洽迭代的过程：

Jul15-2020> <17:59:02>  >>>> CORORT
<Jul15-2020> <17:59:02>  >>>> CLSMAT
<Jul15-2020> <17:59:02>  >>>> ORTHON
<Jul15-2020> <17:59:02>  >>>> GENPT
<Jul15-2020> <17:59:02>  Block Length= 128
<Jul15-2020> <17:59:02>  >>>> PTBAS
<Jul15-2020> <17:59:04>  >>>> CYCLE
<Jul15-2020> <17:59:08>  Spin 1Set  1Initial Constraints: 0.11500000000000E+02
<Jul15-2020> <17:59:08>  Spin 2Set  1Initial Constraints: 0.11500000000000E+02
<Jul15-2020> <17:59:08>   ==> CDFT: constraining charge only
<Jul15-2020> <17:59:08>   ==> New CDFT calculation
<Jul15-2020> <17:59:09>              |Error|         MaxErr       Wt(A-DIIS)
<Jul15-2020> <17:59:09>      1     12.08432412      0.69447419
<Jul15-2020> <17:59:13>      2      1.94388440      0.12393508    100.0
<Jul15-2020> <17:59:14>   CDFT converged in   44 iterations
<Jul15-2020> <17:59:17>      3      0.92925582      0.07717285    100.0
<Jul15-2020> <17:59:19>   CDFT converged in   42 iterations
<Jul15-2020> <17:59:22>      4      1.25040843      0.10040657    100.0
<Jul15-2020> <17:59:24>   CDFT converged in   32 iterations
<Jul15-2020> <17:59:27>      5      0.50153097      0.03730934     36.7
<Jul15-2020> <17:59:28>   CDFT converged in   40 iterations
<Jul15-2020> <17:59:32>      6      0.74086752      0.05969209    100.0
<Jul15-2020> <17:59:33>   CDFT converged in   31 iterations
<Jul15-2020> <17:59:36>      7      0.58744094      0.03926156    100.0
<Jul15-2020> <17:59:37>   CDFT converged in   33 iterations
<Jul15-2020> <17:59:40>      8      0.14618167      0.01428787     13.4
<Jul15-2020> <17:59:41>   CDFT converged in   27 iterations
<Jul15-2020> <17:59:44>      9      0.15237075      0.01669448     13.4
<Jul15-2020> <17:59:45>   CDFT converged in   23 iterations
<Jul15-2020> <17:59:48>     10      0.04846370      0.00322339      2.2
<Jul15-2020> <17:59:49>   CDFT converged in   26 iterations
<Jul15-2020> <17:59:52>     11      0.01277386      0.00088450      0.0
<Jul15-2020> <17:59:54>   CDFT converged in   38 iterations
<Jul15-2020> <17:59:57>     12      0.00701702      0.00052408      0.0
<Jul15-2020> <17:59:58>   CDFT converged in   29 iterations
<Jul15-2020> <18:00:01>     13      0.00542413      0.00042540      0.0
<Jul15-2020> <18:00:03>   CDFT converged in   36 iterations
<Jul15-2020> <18:00:06>     14      0.00311121      0.00027062      0.0
<Jul15-2020> <18:00:07>   CDFT converged in   23 iterations
<Jul15-2020> <18:00:10>     15      0.00127281      0.00008939      0.0
<Jul15-2020> <18:00:11>   CDFT converged in   25 iterations
<Jul15-2020> <18:00:14>     16      0.00032242      0.00002445      0.0
<Jul15-2020> <18:00:15>   CDFT converged in   24 iterations
<Jul15-2020> <18:00:18>     17      0.00022234      0.00002390      0.0
<Jul15-2020> <18:00:19>   CDFT converged in   23 iterations
<Jul15-2020> <18:00:22>     18      0.00007651      0.00000564      0.0
<Jul15-2020> <18:00:23>   CDFT converged in   23 iterations
<Jul15-2020> <18:00:25>     19      0.00006136      0.00000541      0.0
<Jul15-2020> <18:00:26>   CDFT converged in   24 iterations
<Jul15-2020> <18:00:29>     20      0.00010297      0.00000960      0.0
<Jul15-2020> <18:00:30>   CDFT converged in   20 iterations
<Jul15-2020> <18:00:33>     21      0.00006008      0.00000479      0.0
<Jul15-2020> <18:00:34>   CDFT converged in   27 iterations
<Jul15-2020> <18:00:37>     22      0.00001474      0.00000108      0.0
<Jul15-2020> <18:00:39>   CDFT converged in   33 iterations
<Jul15-2020> <18:00:42>     23      0.00000475      0.00000042      0.0
<Jul15-2020> <18:00:43>   CDFT converged in   27 iterations
<Jul15-2020> <18:00:44>  SCF converged
<Jul15-2020> <18:00:46>     24      0.00000923      0.00000077      0.0
<Jul15-2020> <18:00:47>   CDFT converged in   18 iterations
<Jul15-2020> <18:00:49>  >>>> TOTEN
<Jul15-2020> <18:00:55>  >>>> POPAN
<Jul15-2020> <18:00:55>  >>>> DEBYE
<Jul15-2020> <18:00:55>  >>>> AMETS
<Jul15-2020> <18:00:55>   Bond Energy          -8.94002996 a.u.
<Jul15-2020> <18:00:55>   Bond Energy        -243.27059290 eV
<Jul15-2020> <18:00:55>   Bond Energy       -5609.95       kcal/mol
<Jul15-2020> <18:00:55>  >>>> POPUL
<Jul15-2020> <18:00:56>  NORMAL TERMINATION

SCM → View → Properties → Atom info → Mulliken charge → Show：

可以看到$CO_2$区域的总电荷量为-1.类似SCM → Level可以查看能级，与一般分子计算没有没有差别。