UT theoretical chemistry code forum

Thanks a lot, Graeme! I think I get it. I'll try and do as you say asap!

Kind regards!
Roberto

Dear Graeme, Thank you very much for your answer. I see what you mean, but still, and this may be a very naive question, I don't know how to find out to which atoms the forces included in the OUTCAR file are linked to, so as to be able to remove their displacements from the DISPLACECAR file. Any hin...

Dear all, I've been running a dynamical matrix calculation in a supercomputer. Unfortunately, the job reached its scheduled 72-hour walltime before all of the desired displacements present in the DISPLACECAR file were computed. I would like to know if there is there a way to restart the simulation w...

Dear Graeme, Much to my amazement, after including LREAL=.FALSE. in the INCAR file for the equilibrium finite difference calculation, I obtained just three imaginary frequencies, that if I understand correctly correspond to the translations. If I delete those three modes, and since both freq.dat fil...

Thank you very much for your quick reply! Looking closely at the saddle, you are right, apparently the NEB calculation found another version of the equilibrium configuration, obtained by a translation of about 0.0066 Ang. However, why is it then that the equilibrium dynamical matrix calculation is n...

Dear Graeme, please find attached two tar.gz files with the main files from the equilibrium and saddle dynamical matrix calculations. Please let me know if you need something else. Thanks a lot for your keen interest in my problem! Roberto[attachment=0]sad.tar.gz[/attachment][attachment=1]eq.tar.gz[...

Hi! Thanks a lot again for your input, Graeme! I have to say that I didn't find any obvious symmetry in the Hessian matrix, at least by inspection. So I tried to set EDIFF=1E-6 and and EDIFFG=-0.001, with ISYM=0. After convergence, I have used EDIFF=1E-8 and EDIFFG=1E-10 for the finite difference ca...

Hello again! After setting EDIFFG=1E-10 according to your advice, there are no zeros in the Hessian matrix, so that all finite difference calculations are complete. Now we are left with two freq.dat files, one for the equilibrium and the other for the saddle point, both having three imaginary freque...

Thank you very much, Graeme! We'll try and do as you suggest, since there are a number of zero rows in the dynamical matrix as seen in modes.dat.
Just one more thing: I think you mean setting EDIFFG=1E-10, with a "plus", not a "minus", is this correct?

Cheers!
Roberto

Hi! Thanks a lot for your quick reply! Please find below the two frequency files, being freq1.dat the one corresponding to the equilibrium state and freq2.dat the one for the transition state. freq1.dat: 46.628538 cm^{-1} ... 1 44.812202 cm^{-1} ... 1 0.000002 cm^{-1} ... 1 0.000001 cm^{-1} ... 1 0....

Hello everybody! I've searched the forum for answers, but answers to similar problems did not help. Excuse me in advance if this has been posed before. After performing a dynamical matrix calculation I obtain two freq.dat files corresponding to the equilibrium and the transition state of a particula...

Dear Graeme, Thank you very much for your excellent piece of advice!! Setting EDIFFG=-10 made a change and now there are 24 force calls, exactly the number of displacements in my DISPLACECAR file. As a result, all frequencies are real at the saddle point; however, the first one at the equilibrium po...

Hi again and thanks for your answer, Graeme! As you suggested, I re-checked the number of force calls in my previous try, and instead of 25 force calls, corresponding to NSW=25 (8 atoms x 3DOF)+1, I found only 3. There is no walltime limit set in the machine, a local cluster, and I found no signs of...

Hi Graeme! Thanks a lot again for your reply! I've checked the Hessian matrix as shown in freq.mat and it's full of zeros! So there are many displacements for which no frequency was calculated. However, I don’t know where to look to check if there was a problem with the calculation at the minimum, a...

Dear Graeme, Thanks a lot for your reply! You were absolutely right. I made a stupid mistake in the calculation and used the wrong executable, one not compiled using your VTSTTools package. The prefactor obtained for the single atom displacement was also of the order of 10^13 Hz as you mentioned. No...