# Tag Info

## Hot answers tagged dipole

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### I generated Wannier centers but am having trouble understanding how they relate to the atoms in my system: there are more Wannier centers than atoms?

H2O has 10 electrons, two of which are oxygen 1s. This leaves you eight electrons. These eight electrons fit onto 4 spatial orbitals in a spin-restricted calculation for the singlet. Determining ...
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### What units are used in Gaussian 16 for dipole derivatives output?

I recently had the same question. After emailing Gaussian support I was informed that the units are indeed $\sqrt{\text{km}/\text{mol}}$. From their reply I also believe that the derivatives are ...
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### Different types of transition dipole moment in ORCA output

You have stumbled across a problem that was described in 1983 in the following way (note that the "40 years" refers to 1943-1983): "Over the past 40 years, many authors have tried to ...
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### ORCA: Dipole moment of LiH from SP calculation

As suggested by Tyberius, I now expand my comment into an answer. The true charge density of a molecule is a sum of nuclear and electronic contributions. While the former is a sum of delta functions (...
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### What is the right way to calculate <A><A>?

The dipole moment is typically a vector quantity, and the "total dipole moment" which is the $A$ in your question description and the black arrow in the figure below, is the vector sum of ...

### 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 ...
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### How do you calculate the change in dipole moment from ground to first excited state using ORCA?

This second dipole moment is almost surely the excited state. You can see the nuclear contributions are identical and the rotational constants are also the same. This means they are both ...
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### Calculating the excited state dipole moment

This looks like it has been addressed on the CCL previously. To summarize and add details for your case, Gaussian can directly calculate the excited state dipole, but you need to add the keyword ...
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### Calculating the excited state dipole moment

There's actually more than one way to calculate the dipole moment, and you can check whether or not the numbers you're obtaining from td=(singlets,nstates=5,root=1) ...

### Methods to determine the vacuum level in 2D compounds in the presence of dipoles

The purpose of the dipole correction is to remove the spurious electric field that arises between the polarized 2d layer and its periodic replica (think of the correction as if it made your ...
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### Different types of transition dipole moment in ORCA output

To give a little background on where these different forms come from, it is related to gauge theory in electromagnetism. We can represent an electromagnetic field through Maxwell's equations using a ...
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### How is the dipole moment defined in Gaussian?

If my memory serves correctly (this CCL post agrees), the origin used for computing the dipole is the center of nuclear charge: $$R=\frac{\sum_i Z_ir_i}{\sum_i Z_i}$$ As you noted, the origin doesn't ...
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### Are electron dipolar spin-spin interactions included in DFT calculations?

No. Magnetic dipole interactions are not included in DFT. In solids, this effect is usually very weak. If you want to calculate it, you can just solve the contribution to the Hamiltonian analytically. ...
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### ORCA: Dipole moment of LiH from SP calculation

Dipole moment in Quantum Mechanicl I dare to expand the answer of wzkchem5, taking into account how I understood (with some math). The dipole moment of molecular system (which is described by wave ...
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### When should I use dipole correction?

With a large enough vacuum, you don't need a dipole correction as badly to get good results. Sometimes the correction can cause convergence issues or problems with single steps giving incorrect ...

### 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 ...
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