# Quantum Espresso¶

Warning

The ARCHER2 Service is not yet available. This documentation is in development.

Quantum Espresso (QE) is an integrated suite of open-source computer codes for electronic-structure calculations and materials modeling at the nanoscale. It is based on density-functional theory, plane waves, and pseudopotentials.

## Using QE on ARCHER2¶

QE is released under a GPL v2 license and is freely available to all ARCHER2 users.

## Running parallel QE jobs¶

For example, the following script will run a QE pw.x job using 4 nodes (128x4 cores).

Warning

The following SLURM script is a draft and requires verification

#!/bin/bash

# Request 4 nodes to run a 512 MPI task job with 128 MPI tasks per node.
# The maximum walltime limit is set to be 20 minutes.
# Remember to replace [budget code] below with your own account code,
# e.g. '--account=t01-queenie

#SBATCH --job-name=qe_test
#SBATCH --nodes=4
#SBATCH --time=00:20:00

#SBATCH --account=[budget code]
#SBATCH --partition=standard
#SBATCH --qos=standard

# Load the relevant Quantum Espresso module
module restore /etc/cray-pe.d/PrgEnv-gnu

srun pw.x < test_calc.in


## Hints and tips¶

The QE module is set to load up the default QE-provided pseudo- potentials. If you wish to use non-default pseudo-potentials, you will need to change the ESPRESSO_PSEUDO variable to point to the directory you wish. This can be done by adding the following line after the module is loaded

export ESPRESSO_PSEUDO /path/to/pseudo_potentials
`

## Compiling QE¶

The latest instructions for building QE on ARCHER2 can be found in the GitHub repository of build instructions: