# FAQ¶

## What is the difference between AMS and the AMS driver?¶

Amsterdam Modeling Suite (AMS) refers to the whole suite which includes the AMS driver for complex potential energy surface tasks with any underlying engine. The AMS bundle further includes the integrated GUI and the compute engines ADF, BAND, DFTB, MOPAC, ReaxFF, UFF, COSMO-RS.

## What is the AMS driver?¶

It’s a driver for running molecular dynamics or exploring the potential energy surface (finding transition states etc.)

It can be used with different modules: ADF, BAND, DFTB, MOPAC, ReaxFF and external engines. And as such you can switch easily between them, e.g. to transfer a Hessian from a low-lying method.

## What will AMS do when one point fails to converge?¶

With AMS2018.103 it will exit with an error.

Starting with r69000, AMS geometry optimizations try to continue even if engine fails to solve for a geometry.

This can happen if there are for example SCF convergence problems in the engine. The energy/gradients might then not be quite correct, but it is probably safe to continue the optimization and hope that things are fine again for the next step. Note that this fix also applies to PES scans, transition state searches, and any other applications that use geometry optimizations internally (e.g. elastic property calculations).