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Questions tagged [dftb+]

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6 votes
1 answer

May I use a DFTB+ result as initial guess for HF or DFT in PySCF?

I would like to use the result of a DFTB+ calculation as an SCF initial guess calculation in PySCF. Is there a way to generate the density matrix of the converged calculation and read it with PySCF to ...
1 vote
1 answer

What is the best way to optimize molecules with 8000 atoms. This includes C,H,O,N,Si

My molecule includes C,H,O,N,Si
5 votes
1 answer

Calculation of DOS from DFTB+?

I am trying to calculate the DOS and PDOS for a graphene-DNA structure. Upon referring the manual, I understand that we need to have charges converged before computing the DOS. Following this, I have ...
2 votes
0 answers

How do I fix the 4 nodes ignored DFTB input file error in the attached input file? [closed]

I am trying to run MD using DFTB+ v 22.2, however, my input fails with the following errors: ...
6 votes
1 answer

How accurate is DFTB+ in reproducing DFT result?

I am trying to study the shifts in the Fermi level of a graphene - ssDNA hydrid system, depending on the identity of the ssDNA. The structures are obtained from a classical MD simulation, and cannot ...
4 votes
1 answer

What is the significance of xtb message: Interaction energies are not physical?

I have been exploring xtb and used it to run docking on an ion pair. I get the message at the end in the .log file. The xyz files of input structures were obtained from Gaussian output files. Is there ...
3 votes
1 answer

Convergence issues in DFTB+ calculations?

I am trying to calculate the Fermi level of a DNA-graphene system. I was able to get the calculations for graphene and DNA strand to converge separately. However, when I try to calculate the same for ...
3 votes
0 answers

DFTB+ parameters for additional atoms

I wonder if anyone here knows about additional atomic parameters and interactions sets for atoms not currently present in the DFTB parameter sets. The parameter sets are located at DFTB parameters. ...
6 votes
0 answers

Differences between DFTB3 energy and HF energy [closed]

I was performing DFTB3 calculation with DFTB+ on water monomer. This is my input. ...
9 votes
1 answer

How do I create geometry files for carbon nanoribbons and molecular junctions for DFTB+?

I am currently learning DFTB+ using the tutorials on the official website : Carbon Nanoribbons : ...