[CP2K-user] how to run brokn spin symmetry calculation with OT

[Matt W]

Yes, you need a broken symmetry guess. 

You can use the BS section in the KIND section (many threads on how to do 
this it is non intuitive) or you can use the 

https://manual.cp2k.org/cp2k-6_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/PRINT/WFN_MIX.html

section to set up your calculation as you are attempting here. Again, it is 
not all that easy to use...

Matt

On Sunday, December 29, 2019 at 2:38:45 PM UTC, Tamas K. Stenczel wrote:
>
> Dear cp2k developers and users,
>
> I am working modelling the combustion of small hydrocarbons and have issue 
> with spin. I am using CP2K 5.1 right now.
>
> I would like to calculate my system in UKS singlet state, with broken 
> symmetry of the alpha-beta channels.  I have understood that this is the 
> expected behavior of a large system with many oxygen molecules and the 
> result should be better than the singlet with RKS or with spin-symmetric 
> UKS (these two give me the same results actually).
>
> Is this possible with the OT methods, how to do it? I have been using 
> OT%DIIS for its performance with SCF convergence. Diag and mixing methods 
> were not as reliable as this so far, but can perform relaxation of 
> multiplicity, which has given me asymetric spins but I cannot use the 
> wavefunctions of that to restart OT from, due to the error:
>
>> *******************************************************************************
>>  *   ___                                                                       *
>>  *  /   \                                                                      *
>>  * [ABORT]                                                                     *
>>  *  \___/    Number of occupied MOs on restart unit larger than allocated MOs. *
>>  *    |                                                                        *
>>  *  O/|                                                                        *
>>  * /| |                                                                        *
>>  * / \                                                          qs_mo_io.F:818 *
>>  *******************************************************************************
>>
>>
>
> some of the input. I have attached an input file of an O2 molecule for 
> example.
> &DFT
>     POTENTIAL_FILE_NAME GTH_POTENTIALS
>     UKS TRUE
>     MULTIPLICITY 1
>     BASIS_SET_FILE_NAME COMBINED_BASIS_TKS32
>     &SCF
>       MAX_SCF 25
>       EPS_SCF 0.0001
>       SCF_GUESS RESTART
>       &OT
>         MINIMIZER DIIS
>       &END OT
>       &OUTER_SCF
>         EPS_SCF 0.0001
>         MAX_SCF 4
>       &END OUTER_SCF
>     &END SCF
>
>
> Thank you very much,
> Tamas K Stenczel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20191229/f5c5d44c/attachment.htm>