THEOS

Here, we provide some standard brief guidelines on how to setup typical Quantum ESPRESSO (PWscf) calculations.

QE input: A safe way to prepare the input for a PWscf calculation with sensible choice of various parameters is to start from the QE input generator, and then add/modify parameters as you see fit. Check your current input files, and if some suggested parameters differ try to understand why. TRY also to switch to the correct ibra - the QE input generator only uses ibrav=0, and while general that's not really good practice.

Choice of pseudopotentials: Please always use the SSSP library, either in the efficiency version (use that as default) or in the precision one. Certain codes or applications might require norm-conserving pseudopotentials, or fully relativistic ones - discuss with Nicola or some senior/expert member what to choose, and for the first test them and compare them with the SSSP results.

Choice of exchange-correlation functional: For 3D systems you should always start from PBEsol; if Van-der-Waals interactions are important, discuss with Nicola or some senior/expert member.

Choice of smearing: For metals, always use Marzari-Vanderbilt (cold) smearing. See also our other tutorial on electronic temperature on this wiki.

Always use OMP_NUM_THREADS=1