UT theoretical chemistry code forum

Dear all, I want to perform a neb calculation,and firstly I set the spring constant=0, after calculation I think all the images locate the MEP, then I use these images as the initial images to set the spring constant=-5.0 to search the saddle point. Because my calculation is so slow, I think this wa...

You could put the initial POSCAR in the directory of 01, then the use the script of diminit.pl (you could find it in the website of http://theory.cm.utexas.edu/vtsttools/scripts/) to generate the second POSCAR with the first POSCAR, and put it in the directory of 02. You also can refer some calculat...

Dear all, I use 14 image to perform a neb running. After some inoic steps, the neb running is still not convergent. The following are the maximum forces on the 11th image: NEB: Forces: max atom, RMS 0.631483 0.179357 NEB: Forces: max atom, RMS 0.440029 0.109492 NEB: Forces: max atom, RMS 0.398472 0....

Thanks a lot, Graeme! But I mean that I want to study an adsorption system, and I use slab model to construct its configuration, and the adsorbed atoms are adsorbed on each side(surface) of the slab, so the system symmetry is S_2 to ensure the two sides have the same structures. But DIMER method nee...

Sorry, I dno't understand your means surely.

Do you mean the problem is related to the energy of the endpoint, or the energy of the endpoint should be provied in these information?

I use the parameters in INCAR GGA=91 IBRION=3 POTIM=0.0 ISYM=0 ISMEAR=0;SIGMA=.1 NSW=200 NPAR=16 EDIFF = 0.1E-03 EDIFFG = -0.1E-01 PREC=med LREAL=FALSE LWAVE=.FALSE. #neb parameters ICHAIN = 0 IMAGES = 3 SPRING = -5.0 LCLIMB = .F. LTANGENTOLD = .F. LDNEB = .F. Whether the reason is that the precisio...

I perform a NEB calculation, but after only one ionic step the calculation is finishced, and it gives the following error information: NEBV Params: ispring,spring,spring2,spower,efirst,elast NEBV Params: 3 5.00000000000000 5.00000000000000 1.00000000000000 0.00000000000000D+000 0.00000000000000D+000...

Thanks for your reply. But I want to know which surface structure of the system I should select when the DIMER running ends? That means the structures of the two surface are different, which one is more reasonable? In my work, I use each surface to construct a system with S_2 symmetrisation to perfo...

I have a system with S_2 symmetrisation. When I perform a dimer calculation, I found the sentence in OUTCAR: [i]IMPORTANT INFORMATION: All symmetrisations will be switched off! NOSYMM: (Re-)initialisation of all symmetry stuff for point group C_1.[/i] After the dimer calculation, the structures of t...

Thanks a lot for your reply so soon!

Now I know how to do it!

Thank you very much again!

that is great!

If I want to know the energy of intermediate state, I only need to perform

a common VASP static calculations, right?

Dear all, I have a question about how to obtain the intermediate states after finding the saddle point with DIMER method. If the NEB method is used, it is easy to get the intermediate states, because before starting a neb calculation a chain of states linking the initial and finals states should be ...

Thanks your replies! I am clear about the choice of fraction. In fact, I use the DIMER method in my work to explore the diffusion path for a rotation between the metastable state A and the final state B. After finding the saddle point for a relatively lowest-energy diffusion path, I want to plot the...

hi, all. I do some tests but still have something unclear. 1) in my optinion, the distance between the two images in 01 and 02, after finding the saddle point, is very short, so if fraction=1.1, the command : interpolate.pl 01/CONTCAR 02/CONTCAR 1.1 will make a image quite near the CONTCAR-02. For e...

Thanks your replies!
I browse the page of http://theory.cm.utexas.edu/vtsttools/scripts/, and find the usage of interpolate
interpolate.pl (POSCAR 1) (POSCAR 2) (fraction)
output: POSCAR.out file, to STDOUT

here, "fraction" is just the distance between the image and the saddle point ?