[CP2K:8553] error in computing dissociation energy
katarína stančiaková
stanc... at gmail.com
Wed Jan 18 11:11:35 UTC 2017
Thank you for the prompt reply,
just to explain: I performed two sets of tests:
1) I used example input files from CP2K to check if I get the same numbers
as in the TEST_FILES (That's reason why I used SZV basis set there).
2) I tested above mentioned reactions always with the same basis set
(TZVP-MOLOPT), box size, poison solvers, convergence criteria, etc. So I
don't think that this might be a problem.
Since I thought that pseudopotential could be "the problem" I tried to
calculate reaction enthalpy of another simple system: 2CO2 -> 2CO + O2
(using the same settings as for previous reactions) and again compared
results with ADF. The difference was about 16 kcal/mol, so I am a bit
surprised that using pseudopotentials might result in a so large
disagreement on such a small systems.
Best,Katarina
Dňa streda, 18. januára 2017 11:45:30 UTC+1 jgh napísal(-a):
>
> Hi
>
> to add to the post of Vladimir:
>
> Be careful with the basis sets (SZV is not reasonable in CH4).
> Be consistent: use the same box and cutoff and Poisson solver for all
> molecules.
> Be aware that pseudopotentials are known to have problems when
> comparing energies for systems with different spin multiplicities.
>
> regards
>
> Juerg
> --------------------------------------------------------------
> 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
> <javascript:>
> Winterthurerstrasse 190
> CH-8057 Zürich, Switzerland
> ---------------------------------------------------------------
>
> -----cp... at googlegroups.com <javascript:> wrote: -----To: cp2k <
> cp... at googlegroups.com <javascript:>>
> From: katarína stančiaková
> Sent by: cp... at googlegroups.com <javascript:>
> Date: 01/17/2017 02:07PM
> Subject: [CP2K:8553] error in computing dissociation energy
>
> Dear CP2K users,
> I did some basic testing on bond dissociation energies on a small set of
> molecules using PBE functional.
> I compared my results with literature (
> http://dx.doi.org/10.1007/s00214-007-0401-8 ) and with results obtained
> using ADF.
>
> However CP2K results are quite different from my reference and ADF. I
> tried to play with settings (e.g. turn off the periodicity), but this did
> not lead to any improvement.
> Afterwards I decided to do some basic testing, using test files.
> Especially I tested following input files:
>
> /tests/QS/regtest-hybrid-4/CH3-PBE0_TC.inp
> /tests/QS/regtest-hybrid-4/CH3-PBE0_TC_LRC.inp
> /tests/QS/regtest-hybrid-4/CH4-PBE0_TC.inp
> /tests/QS/regtest-hybrid-4/CH4-PBE0_TC_LRC.inp
>
> However, for CH4 case I obtained quite a difference between the numbers
> given in txt TEST_FILES, where I assume numbers which I should obtain are
> stores. I tested two versions of CP2K (4.0 and 2.6), and numbers are still
> the same. Now I am struggling what might be wrong. Please, do you have any
> suggestions?
>
> Below you can find example of input files and my data
>
> (for all cases we assume homolytic dissociation)
>
> CH3-CH3 -> CH3 + CH3 92.59 (96.79) kcal/mol
> CH3-OCH3 -> CH3 + OCH3 81.48 (87.24) kcal/mol
> CH3-isopropyl -> CH3 + isopropyl 86.01 (89.65) kcal/mol
> OCH3 - isopropyl -> 77.69 (84.08) kcal/mol
>
> Numbers in parentheses are from literature.
>
> The results from testing files:
> CH3-PBE0_TC.inp -7.98384 (-7.94392) a.u.
> CH3-PBE0_TC_LRC.inp -7.34353 (-7.34351) a.u.
> cCH4-PBE0_TC.inp -7.35850 (-7.35848) a.u.
> CH4-PBE0_TC_LRC.inp -8.00130 (-7.96099) a.u.
> Numbers in parentheses are from corresponding TXT file TEST_FILES
> (/tests/QS/regtest-hybrid-4/)
>
>
> Thank you for any help
> Best,
> Katarina
>
>
>
>
>
> --
>
> 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+... at googlegroups.com <javascript:>.
>
> To post to this group, send email to cp... at googlegroups.com <javascript:>.
>
>
> Visit this group at https://groups.google.com/group/cp2k.
>
> For more options, visit https://groups.google.com/d/optout.
>
>
>
> [attachment "CH4-PBE0_TC_LRC.inp" removed by Jürg Hutter/at/UZH]
> [attachment "CH4-PBE0_TC_LRC.out" removed by Jürg Hutter/at/UZH]
> [attachment "geo_opt_isopropyl.inp" removed by Jürg Hutter/at/UZH]
> [attachment "geo_opt_isopropyl.out" removed by Jürg Hutter/at/UZH]
> [attachment "Results.pdf" removed by Jürg Hutter/at/UZH]
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20170118/601625b3/attachment.htm>
More information about the CP2K-user
mailing list