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15 votes
Accepted

Best partial atomic charges estimate for crystal field purposes?

There are a few recent atomic partial charge schemes that are useful. You mentioned the electrostatic fitting schemes. These seek to best match the electrostatic potential of the molecule / system, ...
Geoff Hutchison's user avatar
10 votes
Accepted

Benchmarking data for Ewald summation algorithms

I have looked for a similar set of benchmarks and haven't found one, unfortunately. Hopefully the data referred to in the comments comes through! In the meantime, I have an MIT-licensed implementation ...
wcw's user avatar
  • 1,893
10 votes
Accepted

How to map the electrostatic potential from GAUSSIAN, on a solvent accessible surface?

The Jmol software is able to plot different surfaces. In the example below, the system is a Mobius strip and the ESP was calculated using MOPAC but as Jmol is full compatible with Gaussian outputs, I ...
Camps's user avatar
  • 23.3k
8 votes
Accepted

Acceleration of 8110823001207866000 m/s^2 by using Coulomb's law: did I do it right?

The other answer correctly pointed out that using $F=ma$ and the mass of the hydrogen atom does not give the exact $a$, and even if one uses the correct relativistic formulas and the correct mass, one ...
wzkchem5's user avatar
  • 9,640
7 votes

Constructing a molecular polarizability tensor from sets of atomic polarizabilities?

Luckily, I had a need to do this recently, so I can answer with more confidence than I had when commenting before. Basically, the procedure is what you described. We need to: (1) compute the ...
jheindel's user avatar
  • 3,534
7 votes

Acceleration of 8110823001207866000 m/s^2 by using Coulomb's law: did I do it right?

"It rises the question, if Columb's law can be useful at such small/atomic scales?" Coulomb's law still plays a role in the Hamiltonian of an atom, but your discussion of "force" ...
Nike Dattani - No Free Time's user avatar
6 votes

3D Poisson equation solver for arbitrary charge distribution?

It would help to know what you need the potentials for, since this will affect the techniques that are necessary to evaluate the potential. Point charges are trivial, as the potential generated by ...
Susi Lehtola's user avatar
  • 19.1k
6 votes

Are there efficient open source implementations of electrostatic potential integrals?

The open-source program Multiwfn (http://sobereva.com/multiwfn/) contains a module that calculates the electrostatic potentials. According to Tian Lu, it has been quite thoroughly optimized for speed. ...
wzkchem5's user avatar
  • 9,640
5 votes
Accepted

Are there efficient open source implementations of electrostatic potential integrals?

If you know the Gaussian basis set and the density matrix, the task simplifies to the calculation of nuclear attraction integrals. The electron density is expanded in the basis set as $$ n({\bf r}) = \...
Susi Lehtola's user avatar
  • 19.1k
4 votes
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Working with charged surfaces

A straightforward way to model the interaction of charged species with a surface is to use a cluster model instead of simulating the surface as a slab with periodic boundary conditions (1). Cluster ...
Antonio de Oliveira-Filho's user avatar
4 votes
Accepted

Could I simulate the applied voltage on the electrode by adding extra electrons in the system?

You have found for yourself that it is not difficult to reduce water if you throw a suitably overwhelming number of electrons at it, but you're also skeptical that this reflects realistic experimental ...
Shern Ren Tee's user avatar
3 votes

When should I use Charge-Charge Interactions, Charge-Dipole Interactions, and Dipole-Dipole Interactions in molecular simulation?

Let's say you are trying to study the formation of hydration shells around ions or something like Antifreeze Glycoproteins (AFGPs). In such cases, it is important that you include charge-dipole and ...
Hemanth Haridas's user avatar
3 votes

What is the polarization catastrophe?

In short, the polarization catastrophe is the fact that the classical description of polarization applied to point dipoles contains a singularity which occurs at a distance which should regularly be ...
jheindel's user avatar
  • 3,534
2 votes

Simulation of electronic potential from nanoparticles interacting with molecules

I already did the same type of calculation but for different system (functionalized carbon nanotube interacting with heavy metals). About your workflow, the only step I will do different is that ...
Camps's user avatar
  • 23.3k
1 vote

References for Electrostatics Calculations Used in Molecular Dynamics

The reason why most molecular force fields stop at point charges and dipoles is they're good enough. What we mean by "good enough" is for the electrostatic potential (ESP) around a classical ...
Shern Ren Tee's user avatar

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