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10

It is very tempting (and often also very useful!) to picture electron spin as an angular momentum vector, similar to a spinning top. Using this analogy, there are two properties (or numbers) of this angular momentum vector that we need in order to describe the electron spin. The first one is the spin itself and this is often designated the symbol $s$. The ...


9

I'm not aware of the Russell–Saunders effect, but the Russell–Saunders coupling scheme is definitely a thing. As you noted, the Wikipedia page on "spin-orbit interaction" doesn't talk about it, but a different Wikipedia page does, and basically tells you the same thing as I will. The answer is... yes and no. The word "coupling" refers to ...


6

Here's what I believe they're trying to say. First, note that the discussion is mostly limited to high spin complexes (3 unpaired electrons out of the 7 d electrons), so the figure you reproduced is only representative of high spin states. Second, recall that when D > 0 (ie left side of figure), the five d orbital energy levels split so that we have three ...


5

An electron is not a wave nor a particle. An electron is usually described as a quantum object with some wave-like properties and some particle-like properties. Some of them, like particularly a spin, do not have direct counterpart in our familiar macro world. It is a kind of a mysterious, specifically quantum property of all elementary particles and atomic ...


3

Holleman/Wiberg states (translation by me) $\ce{Co^{3+}}$ usually forms octahedral low-spin complexes, because it is the only way to achieve a high ligand-field stabilization energy. Octahedral high-spin complexes are typically an exception; they are formed with the "weakest" ligands (fluoride): $\ce{[CoF6]^{3-}}$, $\ce{[CoF3(H2O)3]}$ (the ion $\ce{[Co(...


3

I'm not a solid-state chemist, but I think the meaning seems reasonably clear from context to me. "Spin degeneracy" here means that each energy level is capable of holding a spin-up electron as well as a spin-down electron, i.e. in each orbital there are two different spin states which are degenerate (some would call these spin orbitals). Thus, $N$...


2

TL;DR Excitation of an electron typically conserves spin; that is to say, the spin must be left unchanged by the process. If the initial state has no net spin (one spin-up and one spin-down electron), then the final state should also have no net spin (one spin-up and one spin-down electron). This rule is reliable for small-ish atoms, but often breaks down ...


2

The picture shows a triplet excited state returning to the ground state by emitting a photon, i.e. phosphorescence. This can only happen if there is also an interaction that couples angular momentum change with the transition, such as spin orbit coupling. The electron has two quantum numbers; the spin $S=1/2$ but is not the spin of the electron that is ...


2

Short answer is that it requires advanced computational methods to determine which state is lower in energy, but we can rationalize the observed result by investigating the behavior of the canonical delocalized molecular orbitals of the $\ce{CH2}$ carbene. What follows here is a summary of information found in chapters 7 and 8 of the second edition of ...


2

The Jahn-Teller effect is not relevant here. The triplet state is observed in many molecules to be of lower energy than the singlet. The Pauli exclusion principle, makes the states symmetric or anti-symmetric to the exchanging electrons. A triplet state has unpaired spins while in a singlet they are paired. The triplet is lower in energy than the ...


2

OK, those who say magnetic fields have no effect can buy a relatively inexpensive Magnetizer (as I once did) and try performing a controlled experiment (as I attempted) with the rusting of iron. There is some apparent evidence that alignment of magnetic fields can promote radical activity. This UK study on the effect of a magnetizer in reducing the amount of ...


1

The strange properties of half-integer spin are one of those mysterious facts that make physics interesting. It's part of the geometry of a mathematical object called a 'spinor'. The name comes from making an analogy with a 'vector', but related to spin. Spinors are fairly advanced mathematics, but there is an intuitive way to think about them that works a ...


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