<div dir="auto">Thanks for the clarification.</div> <div class="gmail_quote"><div dir="ltr">On Tue, 12 Feb 2019, 2:48 p.m. Tiziano Müller <<a href="mailto:tiziano...@chem.uzh.ch">tiziano...@chem.uzh.ch</a> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On 12.02.19 10:04, <a href="mailto:ahadal...@gmail.com" target="_blank" rel="noreferrer">ahadal...@gmail.com</a> wrote: > Can someone elaborate me the difference between the when defining the element: > > Cu GTH-PADE-q11 GTH-LDA-q1 This does not seem right. Did you truncate/augment it when copy/paste'ing? > > Cu GTH-PADE-q11 GTH-LDA-q11 > > Cu GTH-PADE-q11 GTH-LDA-q19 > > In pseudopotentials database. The number after the `q` describes the number of valence electrons in that pseudopotential and should match the basis set being used in the calculation. The names after the element are aliases. Example: Cu GTH-PADE-q11 GTH-LDA-q11 GTH-PADE GTH-LDA ... can be referenced in your calculation with one of the following: POTENTIAL GTH-PADE-q11 or POTENTIAL GTH-LDA-q11 or POTENTIAL GTH-PADE or POTENTIAL GTH-LDA If there are multiple pseudopotentials for the same element and functional, there is usually one (and only one) which has an alias without the '-q??'. > And how to know which one is appropriate while calculating energy and forces. Which one to use depends on your type of calculation and the structure you are trying to simulate. The larger the number of electrons, the more computationally expensive your calculation will be. Best, Tiziano -- Tiziano Müller University of Zurich Department of Chemistry Winterthurerstrasse 190 CH-8057 Zürich Tel: +41 44 63 54234 <a href="http://www.chem.uzh.ch" rel="noreferrer noreferrer" target="_blank">www.chem.uzh.ch</a> <a href="mailto:tiziano...@chem.uzh.ch" target="_blank" rel="noreferrer">tiziano...@chem.uzh.ch</a> </blockquote></div>