AMS driver's tasks and properties
*********************************

The QuantumESPRESSO engine is an engine used by the AMS driver.

The definition of the system, the selection of the task and certain
(potential-energy-surface-related) properties are documented in the
AMS driver's Manual.


Geometry, System definition
===========================

The definition of the system, i.e. the atom types, atomic coordinates,
and lattice vectors (and optionally, atomic masses for isotopes) are
part of the AMS driver input. See the System definition section of the
AMS manual.

Note:

  The Quantum ESPRESSO engine can work with periodic systems (1D, 2D,
  and 3D) and molecular systems (0D). Technically, Quantum ESPRESSO
  only supports 3D periodicity, but the AMS driver will automatically
  place the system in a sufficiently large box to minimize spurious
  interactions between periodic images (G.J. Martyna, and M.E.
  Tuckerman, J. Chem. Phys. 110 (1999) 2810). The QE option
  "assume_isolated" (available in the AMS QE section "System") can be
  used to apply additional corrections to this approximation, but the
  user has to set it up explicitly, except for 0D systems where
  "assume_isolated = 'martyna-tuckerman'" is used by default.


Tasks: exploring the PES
========================

The job of the AMS driver is to handle all changes in the simulated
system's geometry, e.g. during a geometry optimization or molecular
dynamics calculation, using energy and forces calculated by the
engine.

These are the tasks available in the AMS driver:

* GCMC (Grand Canonical Monte Carlo)

* Geometry Optimization

* IRC (Intrinsic Reaction Coordinate)

* Molecular Dynamics

* NEB (Nudged Elastic Band)

* PESScan (Potential Energy Surface Scan, including linear transit)

* Single Point

* Transition State Search

* Vibrational Analysis


Properties in the AMS driver
============================

The following properties can be requested from the QuantumEspresso
engine in the AMS driver's input:

* Elastic tensor

* Hessian

* Nuclear gradients (forces)

* Normal modes

* PES point character

* Phonons

* Stress tensor
