Search found 28 matches

by sxd375
Thu Mar 08, 2018 3:45 pm
Forum: VTSTTools
Topic: dimer method - deviate giving high forces
Replies: 11
Views: 27458

Re: dimer method - deviate giving high forces

Thanks But when I use IBRION 1 with some POTIM, I get the error : CHAIN: Must set IOPT>0 to use the Dimer method That means dimer can only work with optimisers not the usual quasi newton. That means I need to use IOPT 1 for LBFGS algorithm with high EDIFF values for accurate curvatures( And I guess ...
by sxd375
Wed Mar 07, 2018 8:07 pm
Forum: VTSTTools
Topic: dimer method - deviate giving high forces
Replies: 11
Views: 27458

Re: dimer method - deviate giving high forces

well Thanks I have another question - can I use IBRION 1 (quasi newton) with low POTIM value and EDIFF 10^-5 in place of IOPT =2 that i am using here( Since IOPT 2 requires curvature calculation and EDIFF 10^-8 requires more running time on the cluster) ? Though i tried IOPT 1 as well, but the DIMCA...
by sxd375
Tue Mar 06, 2018 1:10 am
Forum: VTSTTools
Topic: dimer method - deviate giving high forces
Replies: 11
Views: 27458

dimer method - deviate giving high forces

Hi I have been running a dimer calculation from NEB which seems to deviate giving high forces as below : Step Force Torque Energy Curvature Angle 1 0.55683 1.55128 -814.42965 -3.31755 2.13037 1 0.55683 1.36002 -814.42965 -3.34471 3.01105 1 0.55683 1.03870 -814.42965 -3.35094 1.87785 1 0.55683 0.7366...
by sxd375
Thu Mar 01, 2018 10:57 pm
Forum: VTSTTools
Topic: improved dimer method paramters tuning
Replies: 5
Views: 16354

Re: improved dimer method paramters tuning

Thanks a lot for your effort.
I was stuck on this for a month.
The lowering of KPOINTS really helps in making the iterations faster.
by sxd375
Fri Feb 23, 2018 3:50 pm
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

Re: NEB jobs donot converge

Thanks As for the bug as u mentioned below: "As a side note, I recently fixed a bug in how the negative mode was being stored and read upon restart. It will not be an issue if you do the entire calculation in a single run, but if you are restarting a dimer calculation, it would make sense to do...
by sxd375
Thu Feb 22, 2018 3:45 am
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

Re: NEB jobs donot converge

Thanks for the suggestion.
However, I ran vibration calculation with IBRION 8, but it ended in 1 NSW saying it cannnot be used with vanderwaals correction ON.
Please suggest.
Thanks
by sxd375
Wed Feb 21, 2018 10:38 pm
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

Re: NEB jobs donot converge

Thanks a lot !! I will try that and see. As for dimer calculation on the above mentioned state, I was getting following high forces and curvatures (so I aborted it): (I used the default parameter values for Ichain = 2 with IOPT = 2) Step Force Torque Energy Curvature Angle 1 0.03822 27.81351 -425.38...
by sxd375
Wed Feb 21, 2018 10:23 pm
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

Re: NEB jobs donot converge

Thanks for the suggestion. However, I didnot understand what u mean by using linear response routine in vasp. And do I need to use ediff 10-8 for frequency calculation ? I am using this INCAR : PREC = NORMAL LREAL = AUTO VOSKOWN = 1 EDIFF = 1E-04 ALGO = Very_Fast ##Updated 8/07 Very_Fast = IALGO 48,...
by sxd375
Wed Feb 21, 2018 10:10 pm
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

Re: NEB jobs donot converge

Yeah so I optimised the highest structure separately with very low POTIM. However, the optimised structure gave multiple imaginary frequencies like -100,-120 and -290 (-100 and -120 corresponds to vibration of the furan ring of C4H3(CH2)O*) which conveys that it is not a first order saddle point. Is...
by sxd375
Wed Feb 21, 2018 8:09 pm
Forum: VTSTTools
Topic: NEB jobs donot converge
Replies: 11
Views: 24153

NEB jobs donot converge

I have been running NEB for C4H3(CH2OH)O* + * ---> C4H3(CH2)O*+ OH* step, the highest image has got forces lesser than -0.05 ev, my EDIFFG criterion, which i checked from outcar which reads as stress matrix after NEB project (eV) -52.47845 -0.42376 -0.07734 -0.42376 -51.58503 0.04778 -0.07734 0.0477...
by sxd375
Tue Feb 13, 2018 4:45 pm
Forum: VTSTTools
Topic: improved dimer method paramters tuning
Replies: 5
Views: 16354

Re: improved dimer method paramters tuning

I tried attaching this file though it didnot show up. so here is the file for NEB.
by sxd375
Tue Feb 13, 2018 4:41 pm
Forum: VTSTTools
Topic: improved dimer method paramters tuning
Replies: 5
Views: 16354

Re: improved dimer method paramters tuning

Please find here attached the files for Dimer run and NEB calculation with IBRION 1( which I am running with POTIM 0.5, though I tried with very low POTIM like 0.1, 0.2 or other optimiser also). The Dimer calculation has been done on the Highest image 03 of the NEB which will be close in structure t...
by sxd375
Tue Feb 13, 2018 3:55 pm
Forum: VTSTTools
Topic: improved dimer method paramters tuning
Replies: 5
Views: 16354

improved dimer method paramters tuning

I have been running the TS state using improved dimer method since cl-NEB failed to converge to the Force criterion -0.05 ev on just one or two atoms, though they came out close to -0.06 ev on these but did not go down further. Hence I did vibration calculation on highest image before using the impr...