Search found 28 matches
- Sun Mar 29, 2020 5:25 pm
- Forum: VTSTTools
- Topic: double negative imaginary frequency after dimer run
- Replies: 2
- Views: 18699
Re: double negative imaginary frequency after dimer run
Hey graeme Thanks for your comments. The vibrational modes are calculated by freezing the surface atoms to save time and just check if the obtained TA state has a single imaginary frequency. I will rerun the dimer calculation as advised and keep you posted. I will check with the linear response meth...
- Tue Feb 04, 2020 4:24 am
- Forum: VTSTTools
- Topic: double negative imaginary frequency after dimer run
- Replies: 2
- Views: 18699
double negative imaginary frequency after dimer run
Hey Dr. Graeme I have been running dimer method for CO oxidation to CO2 on Pd adatom over ceria 100. However, I am getting significant double negative frequencies on vibration calculation for converged dimer TS structure. Is there anything you would suggest to further refine the dimer run and remove...
- Thu Aug 08, 2019 4:29 pm
- Forum: VTSTTools
- Topic: Dimer calculation -consistent high torque
- Replies: 7
- Views: 22795
Re: Dimer calculation -consistent high torque
Hey Graeme I agree with the NEB/dimer at cheap settings, however sometimes the reconverging the TS state back to the original settings and higher kpoints take time (I generally use POTIM 0.05/0.1 for reconverging). As for the high torque, I have been getting them on other systems as well. I will see...
- Mon Aug 05, 2019 4:46 pm
- Forum: VTSTTools
- Topic: Dimer calculation -consistent high torque
- Replies: 7
- Views: 22795
Re: Dimer calculation -consistent high torque
Also found out the following warning errors through out the log files and OUTCAR files. WARNING in EDDRMM: call to ZHEGV failed, returncode = 6 3 4 with different numbers each time during each SCF cycles. The SCF cycles still converge though even after these warnings. Such errors have been suggested...
- Mon Aug 05, 2019 3:21 pm
- Forum: VTSTTools
- Topic: Dimer calculation -consistent high torque
- Replies: 7
- Views: 22795
Re: Dimer calculation -consistent high torque
Thanks for taking time to converge the dimer. However, as I see - I need to redo a geometric optimisation with the original kpoints and original slab width to get the correct energy. I still do not understand the origin of high torque as I described earlier, though lower kpoints and lower ENCUTs and...
- Sun Jul 28, 2019 3:39 pm
- Forum: VTSTTools
- Topic: Dimer calculation -consistent high torque
- Replies: 7
- Views: 22795
Re: Dimer calculation -consistent high torque
Dr. Henkelman Thanks for your reply. Yes the SCFs are converging well here. Please find attached the current run below with the input parameters. Just to tell you about the system that I am running it on :it is a PdO on ceria100 surface for CO to CO2 conversion where oxygen from one side are taken t...
- Sun Jul 28, 2019 2:17 pm
- Forum: VTSTTools
- Topic: Dimer calculation -consistent high torque
- Replies: 7
- Views: 22795
Dimer calculation -consistent high torque
Hi all I have been running a dimer caluclation for TS state (CO to CO2 conversion on ceria 100 surface), however I have been getting consistently high torque which does not drop as the dimer rotates, as below for DROTMAX = 5 (I have tried already with DROTMAX = high values like 50): Step Force Torqu...
- Sun May 06, 2018 5:01 pm
- Forum: VTSTTools
- Topic: Dimer method using IOPT 1 breaks the adsorbate molecule
- Replies: 0
- Views: 80959
Dimer method using IOPT 1 breaks the adsorbate molecule
Dr. Graeme I have been running dimer for a transition state with LBFGS optimiser, with default values other than INVCURV = 0.005 (I read in the forum, it makes the optimiser rather conservative in taking steps). However, the adsorbate molecule breaks off and drifts apart in some 200th iteration lead...
- Fri May 04, 2018 2:55 am
- Forum: VTSTTools
- Topic: geometric Reoptimise Transition state with original KPOINTS after dimer/NEB
- Replies: 3
- Views: 15680
Re: geometric Reoptimise Transition state with original KPOINTS after dimer/NEB
OK
As then what do you suggest for re-optimisation if lower POTIM values do not work and higher POTIM takes the strucutre away from the obtained TS state ?
thanks
As then what do you suggest for re-optimisation if lower POTIM values do not work and higher POTIM takes the strucutre away from the obtained TS state ?
thanks
- Thu May 03, 2018 5:42 pm
- Forum: VTSTTools
- Topic: geometric Reoptimise Transition state with original KPOINTS after dimer/NEB
- Replies: 3
- Views: 15680
geometric Reoptimise Transition state with original KPOINTS after dimer/NEB
Dr. Graeme As suggested by you in this forum throughout, during a dimer or NEB run approaching forces lesser than 0.1 ev, I lower the constraints on KPOINTS from original to 1 1 1 which lets the run computationally faster and I get the Transition state with this lowered KPOINTS. However, when I try ...
- Tue Mar 27, 2018 4:10 pm
- Forum: VTSTTools
- Topic: curvature turns to positive value - dimer
- Replies: 2
- Views: 13462
curvature turns to positive value - dimer
Hi Dr. Graeme I have been running dimer calculation from NEB (when the forces dropped to 0.1 ev) with IOPT 3 (deafult values )and 10^-7 EDIFF. However as found below in the DIMCAR (a part of it), the curvature turns to positive value in the 2nd dimer step and remains positive. 1 3.20328 1.19596 -559...
- Wed Mar 21, 2018 3:06 pm
- Forum: VTSTTools
- Topic: dimer method - deviate giving high forces
- Replies: 11
- Views: 29900
Re: dimer method - deviate giving high forces
Great Thanks
- Tue Mar 20, 2018 3:03 pm
- Forum: VTSTTools
- Topic: dimer method - deviate giving high forces
- Replies: 11
- Views: 29900
Re: dimer method - deviate giving high forces
Dear Dr. Graeme
please let me know if you have any updates on this.
Thanks
please let me know if you have any updates on this.
Thanks
- Wed Mar 14, 2018 12:33 am
- Forum: VTSTTools
- Topic: dimer method - deviate giving high forces
- Replies: 11
- Views: 29900
Re: dimer method - deviate giving high forces
[quote=sxd375 post_id=9757 time=1520453277 user_id=8521] 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 th...
- Thu Mar 08, 2018 4:14 pm
- Forum: VTSTTools
- Topic: dimer method - deviate giving high forces
- Replies: 11
- Views: 29900
Re: dimer method - deviate giving high forces
Sorry to bother u again. I continued the dimer run as posted in the beginning of this thread and I got following DIMCAR with IOPT 2 : Step Force Torque Energy Curvature Angle 1 2.04134 1.05964 -815.09297 -2.71707 1.46944 1 2.04134 0.94002 -815.09297 -2.73440 2.58905 2 2.18434 1.52218 -815.17822 -2.3...