11 votes

Quantum chemistry in external electrostatic field?

Electrostaic embedding is usually on the QM-side as simple point charges which add to the total hamiltonian of the nuceli+electrons. It should be just a simple coulumb interaction. Any modern ...
  • 111
9 votes

Analyzing MD trajectory: molecule orientation

So, with a lot of tries and errors I've found out how to perform such analysis. I'm using a library for Python called MDAnalysis. It can load Gromacs topologies and extract charges from them. Using ...
  • 2,323
8 votes
Accepted

Quantum chemistry in external electrostatic field?

vkj's answer addressed the third part of the question. I'll answer the first part. Which quantum chemistry methods can be used in an external electrostatic field? Also which software supports that? I'...
  • 15.1k
7 votes
Accepted

How to generate a .tpr file from a .pdb or .xyz file in gromacs

For generating a tpr file, you need a topology file (.top), a coordinate file (.gro/.pdb) and a input parameter file (.mdp). Assuming, you are working with amber forcefield (a99ffSBdisp), Here's how I ...
  • 974
7 votes

Adding external electric field in ORCA with specific strength

From the ORCA forum thread: Actually there is an undocumented feature for this purpose: ...
  • 19.3k
7 votes

Electric Field Calculations in VASP

I think VASP has limited electric field ability right now, but someone may come along later and correct me. If you have a surface in the Z direction, you could enable an electric field as such. ...
6 votes

Modelling ion Drift-Diffusion under an external electric potential, convergency in PDE?

These PDEs are typical diffusion-drift PDEs that arise in a huge number of fields (including my field, which is electrochemistry) and are routinely solved using any numerical method of your choice, e....
  • 919
4 votes
Accepted

What are the more efficient, or easier, methods of handling electromagnetic interactions?

You could simplify long range interaction by reducing precision with range. Useful algorithm for it is: https://en.wikipedia.org/wiki/Barnes%E2%80%93Hut_simulation It is usually used for gravity, but ...
4 votes

VASP error when trying to do calculations in the presence of an electric field

I assume that you have relaxed your geometry structure and can perform the VASP calculation. And I support the necessary input cards for SCF and NSCF calculations below. SCF calculation to obtain the ...
  • 14k
4 votes

Reading in E-field with CP2K

From looking at the very long wavelength you specified, I assume your intent is to apply a static field to the calculation? I read here that EFIELD is intended for ...
4 votes
Accepted

COSMO Model and Electric Potential on the Surface of the Cavity Inside Perfect Conductor

First of all, the method used in chemical engineering for calculating chemical potential and similar quantities (actitvity coefficients) for solutes in solutions/mixtures is called COSMO-RS and not ...
  • 116
3 votes

Quantum chemistry in external electrostatic field?

Check DFTB+ with its xtb implementation. Among DFT codes working with ASE, take a look on GPAW, where you also have an external field option.

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