# Tag Info

### How to understand the spin of exciton?

As you mentioned in the question, excitons are indeed bound electron-hole pairs. They are often considered to be the signature of optical spectra in insulating solids. Adding onto the comment by tmph, ...

### How many spin states do Cu+ and Cu2+ have and why?

Often when one is asked for the number of spin states, we are interested in determining the spin state of metal complexes containing these ions, rather than the lone ion itself. If you are interested ...

### How many spin states do Cu+ and Cu2+ have and why?

$\ce{Cu}^+$ This ion has 28 electrons. If all of them are up (i.e. aligned with the +z axis), then since each electron has a spin of magnitude 1/2, we would have a total spin of +14. If all of them ...

### Spin State of Transition Metal complex

For computing the spin-state in a metal complex there are many methods available. I'll focus in DFT as one of the most used methodologies. In a single atom cluster (sometimes described as mononuclear ...

### When should spin polarized calculations be done?

Unfortunately, without performing spin polarized calculations you cannot know if it will matter. Further, you must perform different magnetic configurations (AFM, FM, PM) to know which is stable. ...
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### Why can't we change the spin angular momentum of electrons with an external optical field?

This has already been asked in several forms in Physics Stack Exchange. Within the semi-classical 'electric dipole' approximation, only the electric field of light interacts with the electron. The ...
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### When should spin polarized calculations be done?

I agree with Tristan that the fool proof method is to do a spin-polarized self consistent calculation and look at the final magnetic moment. If the final magnetic moment is non-zero you should include ...

### How to automatically plot atomic structures with magnetic moments?

This took some digging, but I can supply at least a partial answer. Assuming you can copy the list of magnetic moments to a list, you could trick whatever software you are using for visualization into ...

### What do we mean by spin-splitting energy?

The word "splitting" seems to occur only in one sentence, over the course of the entire paper that you referenced: "The d-orbital spin-splitting energy is stronger than the weak ...
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### How to find out the multiplicities of molecules containing d and f block species?

With metals, they can often exist as different multiplicities depending on the compound they are in and it is not always simple to predict the correct multiplicity. More often than not, determining ...
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### Spin considerations for the bandgap and optical excitations

I don't think we need to talk about driving forces (this sounds esoteric) instead calculating the selection rule: $$P_T = \int \psi_1^* \mu \psi_2 d\tau$$ Here $\psi_1$ and $\psi_2$ are the ...

### Why can't we change the spin angular momentum of electrons with an external optical field?

well, you certainly can change the spin of an electron through acting on its orbital motion with the electric field. It is called "spin-orbit coupling" (SOC) and a lot of magneto-optical and ...

### Why can't we change the spin angular momentum of electrons with an external optical field?

I think the claim assumes linear polarization of the light which has zero angular momentum. For circularly polarized light, the spin of the electron should be flipped. (e.g. Appl. Phys. Lett. 114, ...

### Can I have a bond formed for only one spin?

Yes, see e.g. the hydrogen molecule cation.
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### How to interpret spin density isosurface figures?

How to interpret this figure below? And what is the meaning of the blue and yellow color around atoms? This figure basically tells you the probability that you can find spin-up and spin-down ...

### How to find out the multiplicities of molecules containing d and f block species?

To obtain the spin multiplicity of the ground electronic state of a molecule, can be extremely hard. In your question you mentioned $\ce{UF6}$ which has 7 atoms, and not all of them being of the same ...
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### What do we mean by spin-splitting energy?

I see now how your initial questions were related, as they all fall under the scope of crystal field theory. I wrote a bit about this in a previous answer. At least in the context of molecular crystal ...
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### What are the precise forms for the SU(2) and rotation matrices in VASP?

The answer you got on the VASP forum here (thank you for giving us that in your question!) said to look in spinsym.F but was not clear at all, especially due to the ...
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### Can crystal field splitting energy or spin-splitting energy be detected in a density-of-states plot? How?

I'm going to reproduce the part of my answer from the linked question that relates to the spin-splitting. I don't believe the spin-splitting or field splitting can be read from the DOS. The way they ...
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### How to predict spin liquid materials with DFT?

I suspect this would be very difficult to do with DFT. A spin liquid is a very subtle magnetic state and DFT, as a method, is not usually good at describing the magnetic states of a system. Spin ...