18
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How to incorporate the effect of spin-orbit coupling in electronic structure calculation
The inclusion of spin-orbit coupling in electronic structure calculations is done by including the interaction between the electron-spin and the orbital angular momentum in the Hamiltonian. Such ...
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16
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How to incorporate the effect of spin-orbit coupling in electronic structure calculation
Basically there are two kinds of approaches which may be found in many text books, L-S coupling and j-j coupling.
L-S coupling means that scalar electronic states (e.g. atomic L-S states and linear ...
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15
votes
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Spin–orbit interaction with DFT
There are options to include spin-orbit coupling in DFT. In general, there are two ways to do it:
Solve Dirac's relativistic equation for the electrons
Incorporate relativistic effects through the ...
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15
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When do relativistic effects need to be explicitly included?
When to include relativistic corrections or modeling of any kind in computational methods is a rather complex one. Full Dirac methods as you asked about (DHF) recapture two important factors, so ...
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12
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Why were no correlation consistent basis sets for potassium contracted for a non-relativistic Hamiltonian?
The answer in part is that not all the elements up through $\ce{Xe}$ have (or had until fairly recently) a nonrelativistic correlation consistent basis set. Specifically, the alkali and alkaline earth ...
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10
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Software for quantum electrodynamics?
GRASP
Allow me to introduce you to GRASP, a software that was written largely by now 92-year-old Ian Grant and now 94-year old (5 days from now) Charlotte Froese Fischer whose PhD supervisor was ...
- 33.6k
9
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How spin-orbit coupling makes spin-forbidden reactions possible?
TL;DR: The statement $[H,S^2]=0$ indeed holds for no-pair (i.e. without considering the production of electron-positron pairs) calculations of hydrogen-like ions, but not for general atoms and ...
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9
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When should I include semi-core electrons in DFT calculations?
I am quoting from the book Materials Modelling Using Density Functional Theory: Properties and Predictions by Feliciano Giustino
How do we decide which wavefunctions should be considered ‘core’ and ...
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9
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Theoretical origins of stereochemistry
Relating to the question about electroweak chemistry: the parity violation effect of the weak force on chiral asymmetry has been considered for quite a while now. A good accessible introduction to the ...
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9
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For which elements should I include spin orbit coupling in Quantum ESPRESSO?
Spin-orbit coupling is related to relativity which is increasingly important for heavier elements.
If you're aiming for ultra-high precision, as in this post on our site: How accurate are the most ...
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8
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For which elements should I include spin orbit coupling in Quantum ESPRESSO?
But in the case of the pseudo-potentials included, should I use fully relativistic pseudopotentials for all three elements?
Yes, you should use the fully relativistic pseudopotentials if you are ...
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7
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Calculating Te chemical shifts with Gaussian
def2-TZVP employs an effective core potential on Te, which describes the innermost 28 electrons only implicitly; this is almost certainly the cause of the problem. I am surprised the program even ...
- 18k
6
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What is the meaning of energy-consistent and shape-consistent in the context of pseudopotentials?
This 2017 paper titled "Shape and Energy Consistent Pseudopotentials for Correlated Electron systems" defines energy-consistent psuedopotentials this way:
"A combined reproduction of ...
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6
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On mass polarization terms
You may find derivation of eqs.120-124 in these notes Normal modes. The true story. helpful in revising your derivation.
Answering the other question: centre-of-mass can always be separated by the ...
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6
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What are some of the advantages and disadvantages when using shape consistent pseudopotentials as compared to energy consistent pseduopotentials
The advantages and disadvantages are discussed in this review paper which was cited in Susi Lehtola's answer to: What are the types of pseudopotentials? and then again in my answr to: What is the ...
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5
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Scalar relativistic Calculation for pseudopotential
There is no scalar-relativistic effect. "Scalar-relativistic" is an approximation to the fully relativistic treatment. The main simplification in this technique is the neglection of spin-...
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5
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In which cases should SOC be included?
Spin-orbit coupling scales as $Z^4/n^3$ where $Z$ is the atomic number and $n$ is the principal quantum number. When you move down the periodic table and the nucleus becomes heavier and heavier, ...
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5
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What are some of the advantages and disadvantages when using shape consistent pseudopotentials as compared to energy consistent pseduopotentials
Shape consistent pseudopotentials are just commonly used for some reason, even though energy consistent pseudopotentials are "the right way to do it".
The reason why shape consistent ...
- 18k
5
votes
How to incorporate the effect of spin-orbit coupling in electronic structure calculation
Spin-orbit coupling effect can be included in electronic structure calculations using variational methods such as fully relativistic four-component Dirac HF or KS approach, or two-component approaches ...
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5
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Why were no correlation consistent basis sets for potassium contracted for a non-relativistic Hamiltonian?
Like many others, the correlation consistent sets start from an MCHF (i.e. small CASSCF) ground state calculation.
For Li and Be the MCHF ground state has S orbitals only, but there's also a low lying ...
- 18k
4
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When should I include semi-core electrons in DFT calculations?
You are making an approximation by including the semicore states in the pseudopotential. Like the name suggests, semicore states aren't really core states; they lie higher up in energy so they may not ...
- 18k
4
votes
When should I include semi-core electrons in DFT calculations?
Many DFT codes use pseudopotentials (for the core electrons) and basis set functions (for the valence electrons) in order to solve the Schrodinger equation. This because simulates each electron ...
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3
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What is the difference, if any, between an effective core potential (ECP) and a pseudopotential?
They are often used as synonyms
Schwerdtfeger's review paper "The Pseudopotential Approximation in Electronic Structure Theory" states that the two terms are used as synonyms in the ...
- 33.6k
3
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How do scalar states with different multiplities make spin-forbidden reactions possible?
No, the presence of scalar states with different multiplicities is only a necessary condition for spin-forbidden reaction to take place (because otherwise there are no spin-forbidden reactions), but ...
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3
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How to generate relativistic pseudo-potential using Vanderbilt USPP that captures spin-orbit coupling?
The spin-orbit effect is something that your code has to be able to do, it is not a property of the pseudopotential.
Here you can find other discussions about it:
How to incorporate the effect of ...
- 22.3k
2
votes
Converging the potential of a dilute binary alloy system using the Coherent Potential Approximation. What troubleshooting options could I take?
I managed to get the converged U$_{0.01}$Cu$_{0.99}$ potential by converging a pure Uranium potential in a Cu lattice. Then by increasing the concentration of Cu and using the old converged potential ...
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1
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For which elements should I include spin orbit coupling in Quantum ESPRESSO?
The spin-orbit coupling is an interested phenomena very present in semiconductor physics (no heavy atoms here). It affects the behavior of electrons and is a very important property explored in the ...
- 22.3k
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