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10

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 localized orbitals [1] (for periodic boundary conditions these are called Wannier functions), the 4 orbitals localize into two covalent OH bonds, and two lone pairs ...


10

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 calculated with respect to the 3N-6 vibrational modes obtained through the application of the Sayvetz conditions as detailed in their whitepaper (Paragraph after Eqn....


10

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 all constituent dipole moments the system (red arrows in the figure below): In your case you have vectors such as: $26.78 \, \hat{x} -6.31\, \hat{y} + 27.17\,...


9

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 them dipole moment for each molecule can be easily calculated and ordering parameters can be calculated from it. Here is the code. It may not be perfect, but it ...


8

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 calculations of the same geometry. You can also see the magnitude of the dipole moment increases in the second calculation. This is very common in excited states. The ...


5

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. Just write a code which takes in the moment, distances between magnetic atoms in expression 1 (https://en.wikipedia.org/wiki/Magnetic_dipole%E2%80%...


4

Yesterday I was browsing the webpage of the biologist Logan Donaldson and agree 100% with this quote: "As structural studies also have a computational component, a willingness to use computers (UNIX-based systems) is a must." Trust me: it is better to learn the command line. I'm speaking from experience since I have had many students working with ...


3

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 sampled in the course of ordinary classical dynamics. More specifically, the polarization catastrophe is the failure that happens when one tries to describe the ...


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