Thank you Stefano. I will try your suggestions.
*NANDHA KUMAR V.* Research scholar, IISER, PUNE. On Sat, Oct 22, 2016 at 9:15 AM, stefano de gironcoli <[email protected]> wrote: > Dear Vikan, > I dont have direct experience on this problem. here a few things i would > look into: > > from your NEB calculation around the TS you should be able to see what the > unstable mode is expected to look like and how many atoms are involved. > If you compute interatomic force constants (IFC) only around a subset of > the atoms there is the problem of how you impose the acoustic sum rule. > One way would be to complete your DynMat using the IFC of the bulk > material (that you could compute separately), and impose ASR on this model. > To stay on the safe side you could set the mass of the atoms that you did > not compute to a very large number so they do not move. > > stefano > > > > On 21/10/2016 17:38, Vikan Manmathan wrote: > > Dear Developers and Experts, > > I am interested in studying diffusion of metal clusters on oxide support. > As a first step, I took a simplest case (adatom hopping) and obtained the > transition state using CI-NEB method. I want to find the rate constant for > the above, I need to know the normal mode vibrational frequencies at > initial and transition states. > > So I calculated the phonon frequencies using frozen atomic coordinate (nat > _todo option only on metal adatom) since the system size is very large. > I expected the transition state to have one less real frequencies (3N-1) > relative to initial state (3N). However, I am getting 3N real frequencies > for the transition state (correct me if I am wrong). > > I have also checked it by including more atoms in the linear response (up > to 33 atoms) but still I got 3N real frequencies for the TS. > > I have attached the input files and the output file generated by dynmat.x > > Any suggestion will be highly appreciated. > > Thanks in advance. > > regards, > > *NANDHA KUMAR V.* > Research scholar, > IISER, PUNE. > > > _______________________________________________ > Pw_forum mailing > [email protected]http://pwscf.org/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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