# ADF is an AMS Engine¶

Starting from AMS2020 ADF is only accessible via the AMS driver program. The standalone program ‘adf’ does not exist anymore. The job of the AMS driver is to handle all changes in the geometry, e.g. during a geometry optimization, using so-called engines like ADF for the calculation of energies and forces.

Important

In the AMS2020 release ADF is an AMS engine. We recommend you to first read the General section of the AMS Manual

If you use ADF exclusively via the Graphical User Interface (GUI), this change should not create any issues. If, on the other hand, you create input files by hand (or you use ADF via PLAMS), then you should be aware that shell scripts for ADF2019 and previous versions are not compatible with ADF2020 and have to be adjusted to the new setup (see also Automatic tool for conversion of ADF2019 shell scripts).

Some of the changes:

• $AMSHOME/atomicdata/ADF directory with ADF basis sets (instead of$ADFHOME/atomicdata)