[CP2K:3171] error in bond dissociation energy of gas phase molecule

[Teodoro Laino]

ops.. sorry my mistake now..
reported relative error is of ~ 1.0E-3 Hartree.. nonetheless..

On Apr 6, 2011, at 1:09 PM, Teodoro Laino wrote:
> 
>> Sure -
>> but for grid steps (fine density grid on which both decoupler are applied) of 0.2-0.3 Angstrom we are comparing errors of 1.0E-5 (MT) with 1.0E-7(WAVELET).
>> Given the intrinsic errors reported by Jun (we are talking about errors of 1.0E-2 Hartree here!) for me the above numbers are comparable (I wish to see all the papers out there with an overall accuracy of 1.0E-5 Hartree :) ).
>> 
>> ciao,
>> Teo
>> 
>> On Apr 6, 2011, at 1:02 PM, hut... at pci.uzh.ch wrote:
>> 
>>> My mistake, I thought I had read OH-.
>>> Regarding the relative accuracy of the decoupling methods, have a
>>> look in the paper  
>>> DOI=10.1063/1.2335442
>>> where the two methods are compared.
>>> 
>>> regards
>>> 
>>> Juerg
>>> 
>>> --------------------------------------------------------------
>>> Juerg Hutter                         Phone : ++41 44 635 4491
>>> Physical Chemistry Institute   FAX   : ++41 44 635 6838
>>> University of Zurich               E-mail:  hut... at pci.uzh.ch
>>> Winterthurerstrasse 190
>>> CH-8057 Zurich, Switzerland
>>> ---------------------------------------------------------------
>>> 
>>> -----cp... at googlegroups.com wrote: -----
>>> To: cp... at googlegroups.com
>>> From: Teodoro Laino 
>>> Sent by: cp... at googlegroups.com
>>> Date: 04/06/2011 12:58PM
>>> Subject: Re: [CP2K:3169] error in bond dissociation energy of gas phase molecule
>>> 
>>> Hi Juerg,
>>> 
>>> the species are not charged - these are all homolytic dissociations.
>>> Nonetheless the H2O2 may have quite a strong dipole and the decoupling may affect the energetics.
>>> 
>>> Just a comment: WAVELET is not superior to MT. The main difference is the cell size. For such small molecules MT may even be better because you can use a smaller cell or at least comparable to the one of WAVELET :).
>>> 
>>> Teo
>>> 
>>> On Apr 6, 2011, at 12:53 PM, hut... at pci.uzh.ch wrote:
>>> 
>>>> Hi
>>>> 
>>>> as you are generating charged species you should use a non-periodic
>>>> steup.
>>>> 
>>>> Try PERIODIC NONE in the &CELL section together with
>>>> 
>>>>  &POISSON
>>>>    PERIODIC NONE
>>>>    PSOLVER WAVELET    <- MT and ANALYTIC could also work but this is best
>>>>  &END
>>>> 
>>>> in the DFT section.
>>>> 
>>>> regards
>>>> 
>>>> Juerg
>>>> 
>>>> --------------------------------------------------------------
>>>> Juerg Hutter                         Phone : ++41 44 635 4491
>>>> Physical Chemistry Institute   FAX   : ++41 44 635 6838
>>>> University of Zurich               E-mail:  hut... at pci.uzh.ch
>>>> Winterthurerstrasse 190
>>>> CH-8057 Zurich, Switzerland
>>>> ---------------------------------------------------------------
>>>> 
>>>> -----cp... at googlegroups.com wrote: -----
>>>> To: cp2k <cp... at googlegroups.com>
>>>> From: Jun 
>>>> Sent by: cp... at googlegroups.com
>>>> Date: 04/06/2011 12:43PM
>>>> Subject: [CP2K:3165] error in bond dissociation energy of gas phase molecule
>>>> 
>>>> Hello everyone,
>>>> 
>>>> We did some testing calculations on bond dissociation energies of HO-
>>>> OH in vacuum using BLYP and B3LYP. We found a large difference from
>>>> reported results using the same functionals in literature; our numbers
>>>> are about 0.5 eV too small for both functionals. We also cross-checked
>>>> the numbers using gaussian program, indeed cp2k gives smaller bond
>>>> dissociation energy. It is not likely to be BSSE, as we use quite
>>>> large basis set TZV2P and also checked QZV2P. It is obvious that we
>>>> got either the total energy of H2O2 too high or the OH energy too low.
>>>> We checked the energy of H2O --> OH + H, which is very close to what
>>>> we found in literature. So, the problem appears to be the too high
>>>> energy of H2O2.
>>>> Also, we checked CH3-CH3, and found the same: CH3-CH3 bond
>>>> dissociation energy is 0.3 eV too small for both functionals compared
>>>> to literature numbers, while the energy of CH4-->CH3+H agrees well.
>>>> The bond dissociation energies (total energies without ZPE) are
>>>> summarised below, and inputs for H2O2-->2OH (H2O2.inp and OH.inp) are
>>>> uploaded.
>>>>                               BLYP             B3LYP
>>>> H2O2-->2OH       2.04 eV (2.67)      1.80 eV  (2.27)
>>>> H2O-->OH+H        5.10 eV              5.16 eV (5.2)
>>>> C2H6-->2CH3     3.64 eV (3.92)       3.69 eV (3.97)
>>>> CH4-->CH3+H    4.69 eV (4.77)       4.75 eV (4.67)
>>>> Numbers in parentheses are from literature. The geometry is optimised
>>>> one taken from literature, which is almost the same as optimised by
>>>> cp2k.
>>>> Can anyone comment on this? Many thanks in advance.
>>>> 
>>>> Cheers,
>>>> Jun
>>>> 
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>>> 
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>> 
>