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Questions tagged [atomic-physics]

Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change. This includes ions as well as neutral atoms and, unless otherwise stated, for the purposes of this discussion it should be assumed that the term atom includes ions.

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Thickness of a target bombarded with deuterium

I need to calculate de thickness of a sheet of Zinc that is being bombarded by deuterium nuclei. I'm given that the fraction of nuclei dispersed below $\theta=90º$ with $T=8MeV$ is $0.9999$ and the ...
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How can photons excite multiple atoms in a szintillator?

For a photon to excite an electron of an atom it typically has to have the exact right amount of energy for the transition. When the photon energy is to low it is pretty clear that the transition can ...
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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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Is discharge tube dangerous?

Are those gas discharge tubes dangerous? I found atom spectra interesting, so I booked a 1.5 hour lab session at a local high school. The physics teacher gave me a few hydrogen tubes, helium tubes, ...
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Does a small amount of fusion occur in the explosion of atomic bombs?

Because of the amount of heat and pressure produced, is it possible that as a side effect of convention fission weapons, a small amount of atoms are fused?
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Imaginary Transmission

Note that the exact context of Rydberg EIT in the following is, I believe, unimportant. In the paper "Nonlinear quantum optics mediated by Rydberg interactions," O. Firstenberg et al. (J. Phys. B. ...
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When will Hund's rules fail?

I heard someone mentioned that Hund's rules do not always work. Looking at atomic spectrum: (https://qudev.phys.ethz.ch/phys4/PHYS4_lecture10v1_2page.pdf page 10 Hg spectrum) How could singlet (with ...
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Finding the value of $r$ for which the radial function, $P(r)$, has a maximum? [on hold]

In my (university) particle physics course, I am asked to find the values of $r$ for which the function $P(r)$ of a $2s$ Hydrogen electron has its maximum values. Here, $r$ denotes the distance in ...
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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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what do you mean by five fold coordination of the Fe site?

I got this paper to study, it says that in FeS2 (100) there is a five-fold coordination of the Fe sites and a threefold coordination of the S sites. what does that mean? is it inferring to the ...
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Why do atoms emit a certain colour of light? (The emission spectra)

We were taught about the emission spectra in class last year, but my teachers couldn't give me an answer to 'what determines the colour of light emitted?'. (they were giving me the answers to the ...
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How does the shape of radioactive material effect its critical mass?

If critical mass is defined by the amount of fissile material required to sustain nuclear fission. Assuming a subcritical mass object, and knowing radioactive materials can merely by chance break ...
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Intensities of K alpha and beta x rays in Silicon [closed]

What is the relation between K alpha 1 and K beta 1 x rays in Si?
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Orbital wave functions and probability density - interpretation issue

The chronology in which concepts are taught in university physics classes I feel sets students up to have to "unlearn" some earlier concepts in order to grasp new ones, and I think it's why I'm stuck ...
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How much energy is in a 75 kg human being? Including atomic and electrical (charge) [closed]

To calculate the energy in 75 kg of mass is easy with E = mc2. But, how to calculate how much charge are in all our atoms? It is, too, a gargantuan amount of energy.
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Why does 'The electron density builds quadratically with distance from the nuclues.'?

I found the statement above on this useful website. http://photonicswiki.org/index.php?title=Atomic_Orbitals_and_Nodes But I am confused. Why would that be the case? Is this based on some exotic ...
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polarization of ordinary light, laser and photons of atomic transition

The light from thermal sources such as a light bulb is unpolarized but the one from a laser is polarized. Why? Is a photon emitted in an atomic transition linearly or circularly polarized and a ...
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If the probability that an alpha will deflect is $1/10000$, for $n$ layers, is the probability is only $1/10000n$?

I have attached a picture of an extract I read on Wikipedia (also in the AQA A-Level Physics specification and textbook). It says that 1/10000 alpha particles deflected in the alpha particle ...
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Why atomic masses are quoted with reference to an isotope?

Is there any fundamental reason why atomic masses are quoted with respect to a certain element such as an arbitrary C-12 isotope whose mass has been set to 12 unit exactly? Previously, chemists have ...
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Why do atoms tend towards electrical stability?

If an oxygen atom has six electrons, then it has an unfilled orbital and the oxygen atom may share electrons from two hydrogen atoms (and form water) in order to become more stable. But why does ...
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What are Towsend Coeffiecents exactly? And are there any tables out there to look them up?

My question is expecially for the gamma coefficent, does it depend from the air? And further how the material of electrodes is involved in Paschen's Law (Electric Arcs)?
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Program for calculating transition amplitudes

I calculated transition amplitudes with MBPT analytically and used Slater-Condon rules. Now I have a very long expression and I would like to solve my matrix elements. Does someone know a program for ...
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Rabi flopping vs. rate equation approach?

In Chapter 7 of C. J. Foot's Atomic Physics, Foot discusses the interaction of a two-level atom with radiation. He derives the phenomenon of Rabi flopping from the Schrodinger equation, using ...
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Question derived from Bernoulli's book “ Hydrodynamica” and his contribution to atomic Theory

Here is the extract from the book Now the weight $π$ is sought which can compress the air $ECDF$ into the space $eCDJ$, the velocities of the particles in either air (the natural and the ...
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Can an electron of an atom be found anywhere? Does it need energy to happen? [closed]

According to quantum mechanics it should be possible. But can it happens when it has so small probability to occur? also if it can happens that means that energy must be provided in order to the ...
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Why is it that when the atom has inversion symmetry, its dipole moment vanishes when the atom is in an eigenstate?

I am now reading my lecture notes on dipole moment and there's a point which confused me. It says that: Let us consider the $|1s\rangle$ and $|2p_x\rangle$ states of a hydrogen atom. The atom has ...
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Quantization of energy [duplicate]

A mirror reflects all electromagnetic waves that fall on it in the visible spectrum. How does the mechanism of reflection work? Is it because when a photon hits an electron, the electron jumps to a ...
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2answers
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Does the dipole moment of an atom modelled as a two level system depends on its frequency?

Consider an atom modelled as a two level system : $$H=\frac{\hbar \omega}{2} \sigma_z $$ $|0\rangle$ and $|1\rangle$ are the ground and excited states that span the Hilbert space. In the Rabi ...
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Does ammonia emit microwaves?

Ammonia has an electric dipole moment which means that there is a charge located on one side of the molecule. The molecule can also exist in an inverted form with the charge located on the other side ...
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1answer
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Predicting spectral lines

In the spectrum of some hydrogen-like ions the three lines are known, which belong to the same series and have the wavelengths 992, 1085, 1215 angstroms. What other lines can be predicted? I don't ...
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2answers
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Momentum Change from Spontaneous Emission

In page 188 of Christopher Foot's book on atomic physics, he talks about the Doppler cooling limit, and how it comes from a random walk caused by spontaneous emission. He claims that each spontaneous ...
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How come the xenon $6s$ state is metastable?

I'm having some trouble puzzling out some aspects of the electronic excitation spectrum of xenon, and I'd appreciate some help with it. This classic paper ─ the first one to pioneer the use of laser-...
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momentum in calculation of Bohr's radius

Some usual calculations of the Bohr's radius (see 2.5 at Feynman's here, or this text here) starts by defining a radius $a$ ( most probable radius ? average radius ? ). Next, from Heisenberg's ...
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What is the time for sufficient decay of plutonium to render an implosion type fission bomb ineffective

Plutonium decays leaving helium. In a mass of metallic plutonium, some of the metal will decay resulting in helium. This makes the plutonium spongy after time. Presumably this sponginess would ...
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$\langle r \rangle$ and orbital energy [duplicate]

Even though $\langle r_{2s} \rangle > \langle r_{2p} \rangle$ based on the following formula $$ \langle r_{n\ell} \rangle = \frac{{a}_{0}}{2}(3{n}^{2}-\ell(\ell+1)) $$ $2s$ has a lower orbital ...
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3answers
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How is an electron ejected in photoelectric effect?

The ejecetion of an electron from a metal occurs when a photon from a sufficiently high energy light is made to fall on metal. My question is that isn't wave capable of doing the same? Is it so that ...
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1answer
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The Pauli Exclusion Principle for more than two particles, applied to the Coulomb Potential

Disclaimer: I've asked a very similar question before (which I can provide if desired, but it shouldn't contain anything that is not stated here), but it was downvoted and eventually deleted for ...
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Can two atoms be a crystal?

In the physics literature, you can often find the term "two-ion crystal", when talking about two ions that are confined in a e.g. Paul trap. How is this possible? Shouldn't a crystal be a structure ...
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How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum?

How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum? What is the logical thinking behind that it will produce a continuous spectrum?
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What are good, reliable databases of atomic spectra?

I am looking for a database of atomic spectra, which contains atomic levels and their energies, electronic configurations, angular-momentum characteristics and lifetimes, and atomic transitions and ...
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1answer
64 views

What happens to the $3d$ and $4s$ levels during the ionisation of a transition metal?

I'm just wondering about the transition state of a transitional metal before (ex: $[\mathrm{Ar}]\, 3d^3 \,4s^2$) and after ionisation (which means $[\mathrm{Ar}]\, 3d^3 \,4s^1$) because before ...
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1answer
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Why not anything like spontaneous absorption?

I understand that the idea of emission or absorption cannot be incorporated in the framework of non-relativistic QM. We need QFT or relativistic QM to explain the creation and annihilation of ...
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1answer
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Can a strong electric field cause the electrons to come out of the atoms?

Can a strong electric field cause the electrons to come out of the atoms, is this how free electron are obtained in a discharge tube?
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Lennard-Jones potential

For the Lennard-Jones interatomic potential, the portion of the graph between r = sigma and r = equilibrium has a negative potential energy (attraction) and a negative force (repulsion). I am trying ...
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About the symmetric spatial part of a two-electron wavefunction: Can it be that $r_1= r_2$ less favoured than $|r_1-r_2|\neq 0$?

The two-electron wavefunction of the ground state of helium is $$ \psi(r_1,r_2)=\phi_{1s}(r_1)\phi_{1s}(r_2)\otimes (|\uparrow_1\downarrow_2-\downarrow_2\uparrow_1\rangle)/\sqrt{2} $$ where $\phi_{1s}...
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Must the total orbital angular momentum quantum number $L$ be less than the principal quantum number $n$? If so, why?

I am studying LS coupling and term symbols. In my textbook, there is an exercise: Why is it impossible for a $2\ ^{2}\text{D}_{3/2}$ state to exist? The answer says, the total orbital angular ...
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Spin-orbit interaction for titanium in the excited state $(3d)^1(4p)^1$

Let's look at a Ti-atom in an excited state with 2 valence electrons $(3d)^1(4p)^1$. What term schemes $^{2S+1}L_J$ do we have for this state considering spin-orbit interaction? My take: For both ...
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1answer
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What drives the charge separation in atoms?

In atoms charges are neatly separated. Instead of pairing which seems natural they all stick together with their peers. What drives this peer behaviour? Why is it stable?
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Understanding the radial distribution function [duplicate]

I am confused why the maximum of the radial distribution function for 2p orbital is closer to the nucleus than that for 2s orbital. Doesnt this mean that there is a higher chance of finding 2p orbital ...
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1answer
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In AMO experiments, how do cold alkali metal atoms remain gaseous?

My focus is on condensed matter physics, so I've never really explored this question although it always seemed curious to me. My "immediate reaction" intuition would dictate that cold metal atoms ...