Hello,

In my QM/MM simulation with Gromacs 2022.3 / CP2K 2023.1, I used non-periodic QM region in the CP2K input file, as I commented out the following lines in the QMMM block:

! &PERIODIC

! GMAX 1.0E+00

! &MULTIPOLE ON

! RCUT 1.0E+01

! EWALD_PRECISION 1.0E-06

! &END

! &END PERIODIC

However, during the simulation, I found that those lines are still active in the newly generated CP2K input files, somehow, Gromacs removed the sign “!” in the simulation, no matter what:

```
&PERIODIC
GMAX 1.0E+00
&MULTIPOLE ON
RCUT 1.0E+01
EWALD_PRECISION 1.0E-06
&END
&END PERIODIC
```

As I already turned the QM box as non-periodic in the QMMM block:

&CELL

A 16.000 0.000 0.000

B 0.000 20.000 0.000

C 0.000 0.000 16.000

PERIODIC NONE

&END CELL

With this combination, I am not sure how the calculations are done. Could someone give me some comments on it? Thanks a lot!

All the best,

Qinghua