Questions tagged [spin]

For questions about "spin angular momentum", spin states, and anything else having to do with spin.

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8 votes
1 answer
328 views

How to detect an "open shell" molecule?

I feel like this is a really stupid question, and I've been ashamed to ask for a while... When I'm about to run some electronic structure calculation on a molecule, how do I know if I need to use an ...
1 vote
0 answers
68 views

Do there exist a theoretically exact DFT method and XC functional, possibly modified from those for closed-shell molecules, for open-shell molecules?

I'm trying to analyse an extremely complex molecule's electron affinity; the molecule is much too large to perform post-HF methods on, meaning that open-shell DFT is the only option available. While I ...
1 vote
1 answer
57 views

nspin and starting_magnetization in Quantum Espresso

In Quantum Espresso, there is a parameter called nspin, which I understand to include in INPUT if there is a paramagnetic species, like $\ce{Fe}$. Thus, we also ...
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4 votes
0 answers
43 views

Localising radicals on groups or atoms in Gaussian

I am interested in computing single point interaction energy between monomers of radicals located specifically on certain groups or atoms. I have been looking at forums and so and it seems that it is ...
4 votes
2 answers
79 views

How to compute spin projections in QE?

It's well known that VASP can print three orthogonal spin projections at each k point corresponding to each band in the file PROCAR controlled by the tags LORBIT and RWIGS. Is there a way to obtain ...
4 votes
1 answer
118 views

What are the precise forms for the SU(2) and rotation matrices in VASP?

Some time ago, I conducted a discussion with Dr. Gui-Bin Liu on topological materials here. One relevant thing he said was: "The format of trace.txt file is only a necessary condition to be used ...
4 votes
1 answer
130 views

Density functional theory and oxygen spin

I would like to perform single-point/geometry-optimization/NEB calculations on systems involving both molecular oxygens and adsorbed oxygens. Reductions by hydrogens are also involved. I am still ...
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6 votes
2 answers
276 views

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

I know that the U atom has four unpaired electrons. Therefore it has a total spin S of 2. This means its multiplicity is 2S+1 = 5. Now consider a complicated molecule such as $UF_6$. In theory all I ...
  • 831
7 votes
0 answers
38 views

Can the anomalous Hall effect only be applied to magnetic materials? [closed]

As I understand the anomalous Hall effect, in materials with a strong spin-orbit coupling, the intrinsic deflection effect is dominant over the side jump and skew scattering effects. In the intrinsic ...
11 votes
1 answer
87 views

Can crystal field splitting energy or spin-splitting energy be detected in a density-of-states plot? How?

What are the signs (if any) in DOS plots that tell us whether we have a big or small crystal-field splitting energy, or spin-splitting energy? I already asked and got an answer to: What do we mean by ...
  • 5,531
11 votes
2 answers
281 views

What do we mean by spin-splitting energy?

What is the meaning of spin-splitting energy as described here?
  • 5,531
9 votes
1 answer
98 views

Can I have a bond formed for only one spin?

I'm making a topological analysis of a nanotube interacting with some metals. The steps for the calculations were: Optimizing the geometry (I am using SIESTA code). Obtain the electronic density for ...
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4 votes
1 answer
355 views

How to interpret spin density isosurface figures?

The figure below shows the spin density isosurfaces of 3x3x1 ScS2 monolayer supercell doped with Mn atoms. This figure was generated using VASPKIT and ...
  • 5,531
8 votes
3 answers
623 views

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

I have read this paper many times: Coupled Spin and Valley Physics in Monolayers of MoS2 and Other Group-VI Dichalcogenides. Interestingly, this paper is also discussed many times in this community, ...
  • 14k
16 votes
2 answers
844 views

How to understand the spin of exciton?

In very recent years, exciton physics has been intensively explored as the emergence of 2D materials. Exciton is a bound electron-hole pair and is bosonic, namely hosting an integer spin. My first ...
  • 14k
5 votes
1 answer
121 views

How to predict spin liquid materials with DFT?

In condensed matter physics, a quantum spin liquid is a phase of matter that can be formed by interacting quantum spins in certain magnetic materials. The novel concept has been realized in many ...
  • 14k
10 votes
2 answers
230 views

Spin considerations for the bandgap and optical excitations

What are the consequences for the bandgap if the conduction band edge and valence band edge are contributed by different spins? Are there any driving forces that prevent an excitation from spin up to ...
13 votes
2 answers
2k views

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

I know an electron can have two spin states, "spin up" and "spin down", but recently I was asked how many spin states do $\ce{Cu^+}$ and $\ce{Cu^{2+}}$ have, and why? Does anyone ...
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13 votes
2 answers
2k views

When should spin polarized calculations be done?

Should the presence of a d block element in the unit cell mandate the need for performing spin-polarized calculations? I wanted to find out the DOS, PDOS, and the band structure. I'm new to DFT and I'...
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11 votes
1 answer
351 views

How to automatically plot atomic structures with magnetic moments?

I work with magnetic materials and I haven't found a way to automatically plot structures with their corresponding magnetic moments. For this specific project I am using VASP. I am trying to plot ...
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14 votes
2 answers
151 views

Spin State of Transition Metal complex

What are the best possible methods and available software to compute the spin-state energetics of transition metal complexes?