Questions tagged [spin]

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

Filter by
Sorted by
Tagged with
4 votes
1 answer
169 views

What is the unit of (Sz) value in the figure of spin texture?

I have generate a figure illustrating spin texture of one band of a type of material. However I do not know the exact value of the color of background which means (Sz) value. The figure was plotted ...
Tieyuan Bian's user avatar
2 votes
1 answer
137 views

'The combination of multiplicity electrons is impossible' in Gaussian

I am trying to calculate the energies of the S1 and T1 states of a molecule with UDFT using Gaussian. For the T1 state, I can successfully use the following input file: ...
Laura's user avatar
  • 1,187
2 votes
1 answer
70 views

How do I determine the charge and spin multiplicity of a system?

I have a compound (5c from here) as below which I wish to optimize in ORCA. However, I am not sure what is its charge and multiplicity. This is an Ir(III) complex. Iridium has a valence configuration ...
farmaceut's user avatar
1 vote
1 answer
83 views

Spin Configuration of Active Space in PySCF

I was running a state averaged CASSCF (4,4) calculation for the first 3 roots of the TMM biradical in PySCF. I wanted to get the spin configuration of the active space but the only information I could ...
Abhishek R Nath's user avatar
4 votes
1 answer
72 views

Table of Largest CI Components in PySCF CASSCF Calculation

I was running a simple CASSCF calculation in PySCF on the TMM biradical. It was a CASSCF (4,4) state averaged calculation where the energies of the first 3 roots were calculated. The simulation output ...
Abhishek R Nath's user avatar
5 votes
1 answer
470 views

What are alpha and beta electrons?

Question The mwfn filetype includes fields for alpha and beta electrons/orbitals/density matrices. What is the definition of alpha and beta electrons; what distinguishes them? For future research, ...
Adam's user avatar
  • 153
2 votes
2 answers
133 views

How to select charge and multiplicity for macro-molecules?

In optimising proteins with DFT/B3LYP, how can we detect the charge and multiplicity of the protein?
PriZarah's user avatar
  • 409
6 votes
0 answers
115 views

Is there a way to set the spin multiplicity in a VASP calculation?

I will greatly appreciate if someone can point to whether I can specify the spin multiplicity of a vasp calculation? I am trying to get the potential energy mapping of a system with neutral slab and a ...
Xdrake's user avatar
  • 541
4 votes
0 answers
209 views

How to calculate singlet-triplet splitting energy with TD-DFT in ORCA?

I wish to reproduce the results from this paper by Truhlar and co-workers, where they treat a spin-forbidden reaction by considering two effective states coupled by a semi-empirical spin-orbit ...
S R Maiti's user avatar
  • 6,841
5 votes
1 answer
91 views

Is it possible to model hBN spin defects/plasmons coupling in COMSOL/Lumerical

Hexagonal Boron Nitride (h-BN) is a promising material for Quantum technologies, see [1]. I want to perform a plasmonic simulation in COMSOL to replicate this paper. But I am not able to find any ...
Subham's user avatar
  • 101
8 votes
1 answer
848 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 ...
Zane Beckwith's user avatar
1 vote
0 answers
93 views

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

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 ...
Kanghun Kim's user avatar
1 vote
1 answer
551 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 ...
DevxAtom's user avatar
  • 149
4 votes
2 answers
485 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 ...
Hongyi Zhao's user avatar
4 votes
1 answer
169 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 ...
Hongyi Zhao's user avatar
4 votes
1 answer
352 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 ...
Okano's user avatar
  • 1,232
6 votes
2 answers
670 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 ...
DJA's user avatar
  • 851
7 votes
0 answers
79 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 ...
Carmen González's user avatar
11 votes
1 answer
120 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 ...
Chi Kou's user avatar
  • 5,793
11 votes
2 answers
425 views

What do we mean by spin-splitting energy?

What is the meaning of spin-splitting energy as described here?
Chi Kou's user avatar
  • 5,793
10 votes
1 answer
106 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 ...
Camps's user avatar
  • 23.3k
4 votes
1 answer
861 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 ...
Chi Kou's user avatar
  • 5,793
8 votes
3 answers
864 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, ...
Jack's user avatar
  • 15.1k
16 votes
2 answers
2k 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 ...
Jack's user avatar
  • 15.1k
5 votes
1 answer
194 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 ...
Jack's user avatar
  • 15.1k
10 votes
2 answers
566 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 ...
Tristan Maxson's user avatar
14 votes
2 answers
3k 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 ...
Lenoir's user avatar
  • 149
14 votes
2 answers
3k 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'...
Anoop A Nair's user avatar
  • 4,476
11 votes
1 answer
607 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 ...
Daniel M.'s user avatar
  • 821
14 votes
2 answers
230 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?
Debasish Mandal's user avatar