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Questions tagged [term-symbols]

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What does molecular term symbol $X^1\Sigma_u$ mean?

I'm confused about the molecular term symbol, for example:$X^1\Sigma_u$ mean. The super script $1$ and big $\Sigma$ was kind of like that of atomic term symbol. However, I'm not sure what does $X$ (...
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Spectroscopic notation for $As$

I’m wondering if I’m approaching hund’s Rules for Arsenic correctly (Ar): (Ar)$(3d)^{10}(4s)^{2}(4p)^{3}$ I started with HR1: Maximize the spin. I have 6 orbitals so I can put one electron in the ...
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What do we mean by curly braces in an atomic configuration?

What do the '{` mean in atomic configurations e.g: 1s(2)2s(1)2p(2){3P}3p(1) 1s(2)2s(2)2p(3){4S}3p(1)
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What does degeneracy and multiplicity in Term symbol mean?

$^{2S+1}L_J$ was the term symbol. I watched a video online saying $2J+1$ was the fold of degeneracy to the term symbol. Specifically, for nitrogen, the term symbol for the lowest energy was $^4S_{3/...
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Term Symbols of Carbon Atom [duplicate]

For a neutral Carbon Atom, the electron (ground) configuration is $1s^2$$2s^2$$2p^2$. I am told that the term symbols $^{3}S_{1}$ and $^{3}D_{1,2,3}$ are forbidden by Pauli Exclusion Principle. May ...
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How to determine symmetry of the system from the term symbol?

I'm studying term symbols. I can derive them mechanically from the electron configuration using the complete table of microstates. Let's consider a typical example - an atomic carbon with the ...
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Ground state of Beryllium (${\rm Be}$)

Why is the ground state of Beryllium (${\rm Be}$) with electronic configuration $[{\rm He}]2s^2$ is $^1S_0$ and not $^3S_1$? The state $^3S_1$ has higher spin multiplicity.
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Electron configuration of atom under LS coupling

We express the state of atom like $(\mathrm{1s})^2(\mathrm{2s})^2(\mathrm{2p})^6(\mathrm{3s})^2(\mathrm{3p})^6(\mathrm{4s})^1$, $^2\mathrm{S}_{1/2}$, for example. This notation supposes the coupling ...
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What does a lower-case letter to the left of a term symbol, as in $\rm{a}\ ^7\rm{S}$, $\rm{z}\ ^7\rm{P^o}$, or $\rm{b}\ ^5\rm{D}$, mean?

I'm a bit puzzled by this: the energy levels of neutral chromium (available by searching for Cr I in the NIST ASD levels database), the term symbols generally have ...
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The Existence of the $^1D$ term and the non-existence of the $^3D$ term?

Yesterday I asked this question concerning the existence of terms. This question is on the same topic. I have been looking at some tables (in Yang and Hamilton (2010), pg 199) at the terms that exist ...
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Using $M_L$ and $M_S$ to determine existence of terms

When it comes to deciding which terms exist for a given configuration I have often seen an argument along the following lines: For the configuration $np^2$ with $S=1$ it is impossible to form a ...
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What do term symbols with a half-integer “$L$” like $^3[3/2]_{1/2}$ mean?

Atomic term symbols are used to notate the angular momentum content of the electronic states of an atom, and are normally written down as $$^{2S+1}L_J$$ where the state has total spin $S$, spin ...
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Why is the specific notation used for term symbols useful?

This has bugged me for a long time. Term symbols describe electronic states of atoms which have well-defined total electronic angular momentum $J$ as well as total spin and orbital angular momenta $...