# Generate an \[atomtypes\] .itp & pmx

**URL:** <https://gromacs.bioexcel.eu/t/generate-an-atomtypes-itp-pmx/417>\
**Category:** User discussions\
**Created:** [July 2, 2020, 7:56pm UTC](https://gromacs.bioexcel.eu/t/generate-an-atomtypes-itp-pmx/417 "2020-07-02T19:56:07Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Dan](https://avatars.discourse-cdn.com/v4/letter/d/eada6e/32.png) [@Dan](https://gromacs.bioexcel.eu/u/Dan)\
**Post date:** [July 2, 2020, 7:56pm UTC](https://gromacs.bioexcel.eu/t/generate-an-atomtypes-itp-pmx/417/1 "2020-07-02T19:56:07Z")

</div>

I am following a pmx tutorial and there is a separate ligand .itp file with just the [atomtypes] directive that is included in the system topology.

[http://pmx.mpibpc.mpg.de/summerSchool2020\_tutorial2/index.html](http://pmx.mpibpc.mpg.de/summerSchool2020_tutorial2/index.html)

Is there a way to generate this [atomtypes] only file with gromacs? Is it required to run an alchemical FEP?