[DFTB-Plus-User] How to use Waveplot in time-dependent calculations like Verlet or ElectronDynamics

[Wanzhen]

Thanks very much for your kindly reply. And the recalculations used in MD seem quite reasonable.

I'm looking forward to the new version of DFTB+.



Best,
Wanzhen

--

---------------------------------------------
Wanzhen He, Ph.D. Candidate
Department of Engineering Mechanics
Tsinghua University
Beijing, China
---------------------------------------------





At 2020-12-04 00:04:30, "Bálint Aradi" <aradi at uni-bremen.de> wrote:
>Dear Wanzhen,
>
>> I’m doing time-dependent calculations using ElectronDynamics and I want
>> to obtain the DFT-density-like charge densities on girds at each timestep.
>> 
>> I’ve read the instructions about Waveplot that both DetailedXml and
>> EigenvecBin files are required to output the .cube file. So my question
>> is how to obtain time-dependent .xml and eigenvec.bin files so that
>> time-dependent  .cube files could be generated.
>
>That is unfortunately currently not possible. At its current
>implementation, Waveplot uses the eigenvectors in order to create the
>molecular orbitals on the grid and to add them up to obtain the total
>density. The electronic dynamics, on the other hand, produces only
>density matrices.
>
>A student of mine currently works on a reimplementation of Waveplot,
>which (apart of being hopefully much more efficient than the current
>one), should also be able to deal with density matrices. With a bit of
>luck, it may get into the 21.1 release (around April/May next year)-
>
>> Also, I guess this is a question for calculations like molecular
>> dynamics, does anyone have any ideas?
>
>For MD, there is a workaround. One just picks the geometries/snapshots
>one wishes to visualize, then recalculates them in individual static
>calculations and visualizes the densities via the eigenvectors with
>Waveplot. Maybe not the most elegant approach, but quite viable. Also,
>it prevents the generation of lot of unnecessary data (as compared to
>outputting the eigenvectors really at every MD-step...)
>
>Best regards,
>
>Bálint
>
>-- 
>Dr. Bálint Aradi
>Bremen Center for Computational Materials Science, University of Bremen
>http://www.bccms.uni-bremen.de/cms/people/b-aradi/
>
>
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