# Help regarding energy minimisation **URL:** \ **Category:** User discussions\ **Created:** [March 17, 2023, 6:42am UTC](https://gromacs.bioexcel.eu/t/help-regarding-energy-minimisation/5990 "2023-03-17T06:42:21Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![Karis](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@Karis](https://gromacs.bioexcel.eu/u/Karis)\ **Post date:** [March 29, 2023, 2:44pm UTC](https://gromacs.bioexcel.eu/t/help-regarding-energy-minimisation/5990/2 "2023-03-29T14:44:26Z")
Hi, this thread might be what you’re looking for, hope this helps! > [@ERROR No such moleculetype NA](https://gromacs.bioexcel.eu/t/error-no-such-moleculetype-na/4318): > > GROMACS version: GROMACS modification: Yes/No I got this error when I run the line: gmx grompp -f em.mdp -c solv\_ions.gro -p topol.top -o em.tpr -maxwarn 10 in the topol.top there is 3 NA atoms :-) GROMACS - gmx grompp, 2020.1-Ubuntu-2020.1-1 (-: GROMACS is written by: Emile Apol Rossen Apostolov Paul Bauer Herman J.C. Berendsen Par Bjelkmar Christian Blau Viacheslav Bolnykh Kevin Boyd Aldert van Buuren Rudi van Drunen Ant… --- _[View the full topic](https://gromacs.bioexcel.eu/t/help-regarding-energy-minimisation/5990)._