[CP2K-user] [CP2K:13555] Hirshfeld charges, neutral system with no zero total Hirshfeld charge

[hut... at chem.uzh.ch]

Hi

there is not enough information to investigate your problem and
to suggest a solution.
In all my tests I get combined Hirshfeld charges < 0.0005.

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
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-----cp... at googlegroups.com wrote: -----
To: cp... at googlegroups.com
From: "Lucas Lodeiro" 
Sent by: cp... at googlegroups.com
Date: 06/28/2020 08:08PM
Subject: [CP2K:13555] Hirshfeld charges, neutral system with no zero total Hirshfeld charge

Hi all,
I want to obtain Hirshfeld charges for a neutral bulk liquid system (372 atoms), but when I compute the Hirshfeld charges, the total system charge is different to zero.
To obtain the charges I set:
                &PRINT
                        &HIRSHFELD
                                FILENAME
                                SELF_CONSISTENT .TRUE.
                                SHAPE_FUNCTION  DENSITY
                        &END HIRSHFELD
                &END PRINT
I explore the four combinations between nonSCf / SCF and density / gaussian shape functions. The SCF does not change the behavior of total charges (just correct the atomic charges as the reference paper explains). The density shape function corrects the total charge from -1.1 to -0.167, but it still remains different from zero. I compute the total charge of an isolated molecule (the charge is different of zero too, but little) and multiply this value for the number of molecules in the bulk liquid system, and I get -0.084, this is a half the bulk total charge. 
I understand there is numerical "noise" and approximations (just 3 decimals), but I am not pretty sure if this is "normal" or I am missing something.

I think if I use more accurate SCF convergence for Hirshfeld charges it could be corrected, but I do not find any parameter that chose it.

Is what I am getting correct?

Regards - Lucas Lodeiro
  
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