[DFTB-Plus-User] saddle point

[Krishna Mohan G.P.]

Dear Ali

Good luck, and if use NEB be sure that both the initial and final state geometries are well converged.[ Moreover try to align these 2 geoms such that to get some kind of symmetry]. Once NEB get converged try to use CI-NEB etc to find saddle point

best

KM


________________________________
 From: Ali Sadeghi <ali.sadeqi at gmail.com>
To: User list for DFTB+ related questions <dftb-plus-user at dftb-plus.info> 
Sent: Monday, January 13, 2014 7:26 PM
Subject: Re: [DFTB-Plus-User] saddle point
 


Dear Krishna and Riccardo,

Thanks for your help. Now, I can do a geometry relaxation within ASE by calling DFTB+. I've not tried the NEB tool but I guess it should also work fine.

Thanks again,
Ali.






On Thu, Jan 9, 2014 at 5:06 PM, Riccardo Petraglia <riccardo.petraglia at epfl.ch> wrote:

Hello,
>
>I am trying it right now... :)
>
>For me it seem to work properly.
>
>This is my input:
>
>from ase.calculators.dftb import Dftb
>from ase import Atoms
>from ase.optimize import QuasiNewton
>from ase.data.molecules import molecule
>from ase.io import write
>
>
>test = molecule('H2O')
>
>test.set_calculator(Dftb(label='h2o',atoms=test,
>Hamiltonian_SCC = 'YES',
>Hamiltonian_MaxAngularMomentum_ = '',
>Hamiltonian_MaxAngularMomentum_O = '"p"',
>Hamiltonian_MaxAngularMomentum_H = '"s"',
>Hamiltonian_MaxSCCIterations = 1000,
>Hamiltonian_ThirdOrderFull = 'YES',
>Hamiltonian_HubbardDerivs_ = '',
>Hamiltonian_HubbardDerivs_O = '-0.1575',
>Hamiltonian_HubbardDerivs_H = '-0.07',
>))
>
>print test.get_potential_energy()
>print test.get_forces()
>
>and I get as energy -110.538574953.
>
>I downloaded the source version of the ASE package and I installed
      it manually. I am using debian wheezy and there is an old version
      of ASE available from the package manager but it does not work
      properly with DFTB+. I noticed that you get errors like yours when
      the computation does not finish well. It could also be due to a
      wrong settings of the required variables (I noticed that you need
      to put a "/" at the end of the paths).
>
>I hope to be useful,
>Riccardo
>
>
>
>On 01/04/2014 04:20 AM, ali sadeghi wrote:
>
>Dear Krishna Mohan, 
>>
>>
>>Thanks for your response. It is a good idea! The NEB example works fine with the  with the EMT calculator, but not with DFTB+. Even the given example (i.e. geometry optimization) does not work in my case because self.atoms.get_forces() fails.
>>
>>
>>Did you (or any body else) try ASE using the  DFTB+ calculator?
>>
>>
>>
>>Best,
>>Ali
>>
>>
>>
>>
>>
>>
>>
>>On Thu, Jan 2, 2014 at 7:34 AM, Krishna Mohan G.P. <gpkmohan at yahoo.com> wrote:
>>>
>>> Dear Ali,
>>>
>>> By using ASE [from https://wiki.fysik.dtu.dk/ase/] you can find Transition state.
>>> Once I tried it and it performed good enough...
>>>
>>> best
>>>
>>> Krishna Mohan G P
>>>
>>> ________________________________
>>> From: ali sadeghi <ali.sadeqi at gmail.com>
>>> To: User list for DFTB+ related questions <dftb-plus-user at dftb-plus.info>
>>> Sent: Friday, December 27, 2013 2:47 AM
>>> Subject: [DFTB-Plus-User] saddle point
>>>
>>> Dear All,
>>>
>>> I'm wondering if there is an implementation for a saddle
          point search.
>>>
>>> Thanks in advance,
>>> Ali Sadeghi
>>>
>>>
>>> _______________________________________________
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>>> DFTB-Plus-User at dftb-plus.info
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>>>
>>>
>>>
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>>
>>
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>
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