difference in HF energies between cp2k and gamess

[pavan kumar behara]

Hello CP2K developers,

I am using CP2K-6.1 and performed HF energy calculations for a Zinc atom and a Zinc cation (Zn+) using GAPW method with an all electron basis. I used RHF for Zinc atom and UHF for the cation. When I use the same basis set and do the same HF calculation with Gamess package (using spherical harmonics), I observed energy differences of the order of 1E-04 in neutral Zinc atom and 1E-02 in the cation with CP2K. Can anyone please explain why I encounter such a huge difference in energies?

Total Energy [a.u.]	Zinc atom (RHF)	Zinc cation (UHF)
CP2K	-1777.4132704603	-1777.1684587898
GAMESS	-1777.4131494803	-1777.1301231505
difference	0.0001209800	0.0383356393

I attached all the inputs and outputs for cp2k as well as gamess for your reference.

Thank you very much for your time, any help is appreciated.

Best regards,

Pavan.

[Matt W]

I'd think you've converged (?) to different electronic states.

[pavan kumar behara]

I am sorry, I didn't get you. I'm still puzzled about the convergence to a different value in case of a single atom. 

[hut...@chem.uzh.ch]

Hi

you should add
&POISSON
PERIODIC NONE
POISSON_SOLVER WAVELET
&END
to the &DFT section (and move the atom to the center of the box).

Further increase the Atomic grid parameters in the &KIND section, e.g.

LEBEDEV_GRID 500
RADIAL_GRID 2500

with this settings and some tighter convergence I get

Zn Atom -1777.4131495436
Zn cation -1777.1301232672

regards

Juerg Hutter

--------------------------------------------------------------
Juerg Hutter Phone : ++41 44 635 4491
Institut für Chemie C FAX : ++41 44 635 6838
Universität Zürich E-mail: hut...@chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp...@googlegroups.com wrote: -----
To: "cp2k" <cp...@googlegroups.com>
From: "pavan kumar behara"
Sent by: cp...@googlegroups.com
Date: 06/25/2019 08:57PM
Subject: [CP2K:11907] difference in HF energies between cp2k and gamess

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[attachment "cp2k_zinc_atom.inp" removed by Jürg Hutter/at/UZH]
[attachment "cp2k_zinc_atom.out" removed by Jürg Hutter/at/UZH]
[attachment "cp2k_zinc_cation.inp" removed by Jürg Hutter/at/UZH]
[attachment "cp2k_zinc_cation.out" removed by Jürg Hutter/at/UZH]
[attachment "gamess_zinc_atom.inp" removed by Jürg Hutter/at/UZH]
[attachment "gamess_zinc_atom.out" removed by Jürg Hutter/at/UZH]
[attachment "gamess_zinc_cation.inp" removed by Jürg Hutter/at/UZH]
[attachment "gamess_zinc_cation.out" removed by Jürg Hutter/at/UZH]

[pavan kumar behara]

Thank you very much for the clarification Prof. Hutter.

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