CMBJ

CMBJ = [real (array)]
Default: CMBJ = calculated self-consistently

Description: defines the $c$ parameter in the MBJ potential.

The CMBJ tag can be set in the following ways:

Specify a constant
```
CMBJ = c
```

Specify one entry per atomic type
```
CMBJ = c_1 c_2 .. c_n
```
where the order and number $n$ $n$ is in accordance with atomic types in your POSCAR file. The MBJ exchange potential at a point $\mathbf{r}$ $\mathbf{r}$ will then be calculated using the parameter $c_{i}$ $c_{i}$ belonging to the atomic species of the atomic site nearest to $\mathbf{r}$ $\mathbf{r}$ .

If CMBJ is not set, it is calculated at each electronic step as the average of $\nabla n_{\sigma}$ in the unit cell, as explained in the description of the METAGGA tag.