[CP2K-user] [CP2K:18258] Re: TS Dimer method gives unphysical results

DMT dobromirak at gmail.com
Mon Dec 26 14:15:48 UTC 2022

Also tried the following settings:

        MAX_ITER 2000
        RMS_DR 0.10E-04                    !DEF 1.5E-3
        MAX_DR 0.30E-04                    !DEF 3.0E-3
        RMS_FORCE 0.10E-04                !DEF 3.0E-4
        MAX_FORCE 0.30E-04                !DEF 4.5E-4
              MAX_STEEP_STEPS 0
                   TYPE 2PNT                                    !WORKS WITH 
                     MAX_ALLOWED_STEP 0.20                !DEF 2.5E-1
                   &END 2PNT
              &END LINE_SEARCH
        &END CG
            METHOD DIMER
                DR 1.0E-2                            !DEF 1.0E-2
                ANGLE_TOLERANCE 2.0                    !DEFAULT 
                INTERPOLATE_GRADIENT T                 !DEFAULT T
                    OPTIMIZER CG
                        MAX_STEEP_STEPS 0
                            TYPE 2PNT                !WORKS WITH CG
                                MAX_ALLOWED_STEP 1.0E-1                !DEF 
                            &END 2PNT
                        &END LINE_SEARCH
                    &END CG
                &END ROT_OPT
            &END DIMER

and nothing changed.
On Monday, December 26, 2022 at 1:15:50 AM UTC+2 DMT wrote:

> and files from the second reaction
> On Monday, December 26, 2022 at 1:14:34 AM UTC+2 DMT wrote:
>> Hello,
>> I tried to use the Dimer method of optimizing TS and I get unphysical 
>> results.
>> I used this google group to find different input files and read about the 
>> struggles to overcome and used the provided input settings of successful 
>> runs.
>> In both cases (files attached include input, required .xyz and output 
>> .xyz from the optimization) Dimer drives the structures into having 
>> impossibly short bonds, until the SCF does not even want to converge (and 
>> it would be obviously impossible). It literally tries to merge some atoms 
>> in both cases. I use the &DIMER_VECTOR to input the XYZ displacements from 
>> a VIBRATIONAL_ANALYSIS job for the Reaction Coordinate that I am interested 
>> in, using the guessed near-TS geometries. Without the DIMER_VECTOR the 
>> method always chooses a wrong Reaction path. In both cases the TS geometry 
>> I start with is very simple to provide, in fact I have found both TS with 
>> other software, it is just very important for me to try simple systems in 
>> cp2k before I move to actual research.
>> One of the reactions is substitution in which the N LP from NH3 attacks 
>> the C of CH3Cl and pushes the Cl away to form a quaternary ammonium cation 
>> with the Cl- around. The other reaction is monomolecular - a keto-O taking 
>> a H from a nearby amino group into an alcohol-imin as a Product.
>> I have already tried higher values for EPS_DEFAULT (1.0E-13) and EPS_SCF 
>> (1.0E-7), and nothing changes.
>> I feel like the Dimer simply doesn't know where to stop with increasing 
>> the Energy. Perhaps the choice of DFT (PBE) and basis (DZVP-MOLOPT-GTH (a 
>> good basis)) is bad for the particular PES ?
>> I would like any advises at all. Do you have success using the Dimer 
>> method ? Can you provide input files from successful runs, other than the 
>> ones already in the group conversations ?
>> Best Regards,
>> Dobromir

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+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/53b199cd-9b76-419b-a5d2-6faeeb1f5ef6n%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20221226/d87faf9d/attachment.htm>

More information about the CP2K-user mailing list