[CP2K-user] [CP2K:17368] Ewald parameters

[Jürg Hutter]

Hi

The same EWALD section is used in different parts of the code (DFT/TB/MM). Some of the parameters
only apply for specific sub-methods (e.g. SPME).
In some cases, there is a redundant set of parameters that allow to achieve a certain accuracy with
different settings (this is due to historical reasons).
Check "Computer Physics Communications 167 (2), 103-128 (2005)" for a complete set of equations
implemented for the GPW DFT case.

regards

Juerg Hutter

________________________________________
From: cp2k at googlegroups.com <cp2k at googlegroups.com> on behalf of Andy <ang.dionysos.gao at gmail.com>
Sent: Saturday, July 23, 2022 8:26 AM
To: cp2k
Subject: [CP2K:17359] Ewald parameters

According to the cp2k manual, there is a ALPHA keyword in the Ewald input section (Section path: CP2K_INPUT<https://manual.cp2k.org/trunk/CP2K_INPUT.html> / FORCE_EVAL<https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL.html> / DFT<https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT.html> / POISSON<https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT/POISSON.html> / EWALD<https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT/POISSON/EWALD.html>). I am not 100% sure about the meaning of ALPHA, but my gut feeling is that ALPHA controls the real space part of the Ewald summation. But as I was going through the cp2k code (specifically the qs_ks_build_kohn_sham_matrix subroutine), I did not find the code that handles the real space part of the Ewald summation. It seems to me that all the Ewald summation are included in the k-space summation. The recent JCP(2020) paper on CP2K suggests that too. So is ALPHA an obsolete parameter?

--
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com<mailto:cp2k+unsubscribe at googlegroups.com>.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/8cb6666b-326a-40d2-a5a6-734e38eb4451n%40googlegroups.com<https://groups.google.com/d/msgid/cp2k/8cb6666b-326a-40d2-a5a6-734e38eb4451n%40googlegroups.com?utm_medium=email&utm_source=footer>.

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/ZR0P278MB075951FD3D2A0CBE46565DB89F959%40ZR0P278MB0759.CHEP278.PROD.OUTLOOK.COM.