20
votes
Accepted
Total spin and/or multiplicity for transition metal ions?
Even for the simplest transition metal diatomic molecules, the most reliable way to know the ground-state spin configuration is often by doing experiments. I will give an example where it's easy to ...
17
votes
Accepted
Does DeepMind's new protein folding software (AlphaFold) also work well for metalloproteins (proteins with metal cofactors)?
It's a great question! Some of my answer will be taken from my answer to your question on the AI stack exchange, but cross-site questions are allowed and your question here is slightly different so my ...
16
votes
Accepted
Berry's curvature and magnetic moment in TMDCs
The Berry curvature is defined as:
$$
\Omega_{\mu\nu}(\mathbf{k})=\partial_{\mu}A_{\nu}(\mathbf{k})-\partial_{\nu}A_{\mu}(\mathbf{k}),
\tag{1}
$$
where $A_{\mu}(\mathbf{k})=\langle u_{\mathbf{k}}|i\...
- 11k
13
votes
Is there a way to obtain solution-phase dielectric constants?
It's possible to estimate solution-phase dielectric constant from a molecular dynamics simulation using this formula:
$$\epsilon_{r} = 1 + \frac{4\pi}{3Vk_{B}T}(\langle \mathbf{P}^{2} \rangle - \...
- 2,934
12
votes
How many spin states do Cu+ and Cu2+ have and why?
$\ce{Cu}^+$
This ion has 28 electrons. If all of them are up (i.e. aligned with the +z axis), then since each electron has a spin of magnitude 1/2, we would have a total spin of +14. If all of them ...
12
votes
Berry's curvature and magnetic moment in TMDCs
Resolution for the time reversal symmetry:
I need to demonstrate: $\Omega(-\mathbf{k})=-\Omega(\mathbf{k})$ (Berry's curvature is a odd function under time reversal symmetry)
Berry's curvature:
$$\...
- 1,763
11
votes
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 ...
- 15.5k
10
votes
Hubbard U correction for Copper
Just to add to Anyon's answer:
Since there may be practical considerations for using DFT+$U$ in a database like the Materials Project (i.e. a value you're confident will give you generally correct ...
- 3,161
10
votes
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 ...
- 1,590
9
votes
Accepted
Physical origin for higher bandgaps when going from bulk to few-layers
Quantum confinement can occur when the exciton (electron-hole quasiparticle) radius is larger than the size of the semiconductor. Due to this confinement, the energy levels which can be occupied by ...
- 11k
9
votes
Total spin and/or multiplicity for transition metal ions?
If you're studying transition metal complexes, in short, there is no simple way to know except for to try the relevant physically plausible spin multiplicities and take the lowest energy solution as ...
- 7,361
9
votes
Accepted
Appropriate functionals for prediction of NMR spectra of transition metal compounds
I haven't had much experience with calculating chemical shifts, but I do have experience calculating J-coupling between P atoms on metal complexes.
From this, I know that for chemical shifts and J-...
- 106
9
votes
Accepted
Why is it so hard to find the ground state of molecules with d-block or f-block elements?
Difficulty in capturing enough electron correlation: The difference between the lowest states belonging to different electronic configurations can be small (for example, on the order of 1 kcal/mol). ...
8
votes
Accepted
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 ...
- 15.5k
8
votes
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 ...
8
votes
What are good basis sets and functionals for Ni, Cd and Pb?
The Karlsruhe def2 basis sets cover most of the periodic table and are based on effective core potentials for relativistic effects; these are a good starting point for whatever you are interested in, ...
- 19.1k
7
votes
Predicting magnetic moment of a metal complex computationally
The main question here is whether the question makes sense for ${\rm K}_3[{\rm Mn(CN)}_6]$ as a molecular complex.
Looks like the material has a solid state structure https://materials.springer.com/...
- 19.1k
7
votes
Accepted
DFT+U Values from Reference Formation Energies
I can't help with the textbook, but the NIST-JANAF Thermochemical Tables are available here:
https://janaf.nist.gov/
- 3,161
7
votes
Hubbard U correction for Copper
I can't speak as to how the Materials Project selects what information to display, but it's clear that the Hubbard $U$ (or rather the correlations/interactions it attempts to capture) generally is ...
- 4,741
6
votes
Accepted
Quantum confinement of transition metal dichalcogenides (TMDs)
Quantum confinement is a kind of physical effect, which describes the change of electronic and optical properties when the material sampled is of sufficiently small size----typically 10 nanometers or ...
- 15.1k
6
votes
Why is it so hard to find the ground state of molecules with d-block or f-block elements?
d-block
The extra difficulty of studying a d-block element/transition metal complex is that the "breaking of degeneracies of electron orbital states" can result in different stable ...
- 8,017
5
votes
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 ...
5
votes
Why is it so hard to find the ground state of molecules with d-block or f-block elements?
Very briefly, in many cases d- and f- orbitals are (quasi)degenerate. So to accurately calculate energies we need to take into account all permutations of electrons over those orbitals (multireference ...
- 2,373
5
votes
Accepted
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 ...
- 15.5k
5
votes
Can the color of gold metal be reproduced by modeling only the conduction electron band structure, or do atomic absorption lines contribute?
A band can either be expressed as a linear combination of plane waves, or as a linear combination of atomic orbitals. By asserting that the color of gold can be explained by relativistic shifts of ...
- 9,621
5
votes
Appropriate functionals for prediction of NMR spectra of transition metal compounds
I do not have much experience with DFT, but have been digging into DFT in strong fields the last couple of months. The investigation of magnetic properties such as NMR shielding constant and the ...
- 1,335
5
votes
Promising functionals for transition metal chemistry
Just to provide an answer to this question, my conclusion after all this is that in general, there is unfortunately not a great answer. I likely put too many constraints on the question.
As noted in &...
- 7,361
5
votes
Accepted
Are there any other options beyond increasing the k-sampling and the number of unoccupied bands, to achieve better results?
After a few months working with Aluminum-based structures, I'm confident to respond to my own question. And the answer is NO.
Keeping in mind that I'm using the IPA (independent particle approximation)...
- 3,320
4
votes
Correlation tables between irreps for f orbitals
The simplest way to check the correlation between $f$-type basis functions in a high-symmetry point group (say $D_{\infty h}$) and in its Abelian subgroup (say $D_{2h}$) or any other subgroup is to ...
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