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, ...

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How do temporary dipole-dipole interactions work in quantum mechanics?

The standard presentation of temporary dipole-dipole interactions (in high school at least) is classical: the electrons in an atom/molecule 'orbit' around its nucleus/nuclei. As a direct result of ...
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18 views

Absorption cross-section in atoms

How could someone calculate the absorption cross-section for an atomic species, not only on a specific atomic resonance, but derive a result, for the dependence of the absorption cross-section from ...
0
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1answer
40 views

Rydberg formula for hydrogen

I've been told that if a hydrogen atom is exposed to electromagnetic radiation of wavelength $\lambda$ such that Rydberg's formula $$\frac{1}{\lambda}=R\left(\frac{1}{n_{1}^2}-\frac{1}{n_{2}^2}\...
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3answers
316 views

Quantum mechanics of the electron in an atom vs. Gryzinski's free-fall atomic model [closed]

According to Heisenberg's Principle of uncertainty, you can not know the place and speed of a particle, at the same time. You only have probabilities of the estimate values. These probabilities forms ...
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1answer
46 views

Thermionic emission

I have a pretty basic question regarding the beam of electrons as a result of thermionic emission. In an electron gun, the emitted electrons from the cathode become incident at a point on the other ...
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1answer
30 views

elelctric potential from a laser

The average intensity from elecreomagnetic waves are given by: $$I=c \frac{E_{av}^2 \epsilon_0}{2}$$ I want to find what strength of a laser one needs to apply to get below the binding energy of a ...
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1answer
29 views

Quantum confined stark effect

As far as the stark effect is concerned, I imagine that the quenching of the emission spectra occurs because of the increase in the distance between the expected values of the electron and hole cloud, ...
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38 views

Can a naked eye see a single atom when it is resonantly driven by some laser beam? [duplicate]

Presumably, when the laser is strong enough, the fluorescence will be very strong too. So, is it possible to see a single atom with a naked eye?
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1answer
48 views

Current due to motion of electron [closed]

The radius of first orbit of hydrogen atom is $0.5 A$ and an electron is moving in this orbit with velocity $2 \times 10^6$ meter/sec, the current due to motion of electron in the orbit will be?
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2answers
77 views

How can only one valence electron in sodium cause doublet in spectrum?

The valence electron in sodium atom gets excited and moves to higher orbital say $3P$ and it then comes to the lower energy state $3S$ thus there should be only one line in spectrum (regarding this ...
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2answers
96 views

Why has a molecule less energy than the uncombined atoms?

My book says, A molecule as compared to the atoms from which it is formed is more stable because it possesses energy lower than the energy of the uncombined atoms. This difference in energy is due ...
0
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1answer
115 views

Does temperature affect to movement of electrons?

Does temperature affect to the movement of the electrons circulating the core of an atom? Do they move faster if temperature increases?
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153 views

Photon absorption by atoms vs compton scattering

In compton scattering, a photon may deliver only some of its energy to an electron. But when dealing with photon electron interaction in an atom, it's all or nothing. Why the difference? Also, ...
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1answer
23 views

Formation of Line Spectra in light of Bohr's Theory [closed]

I am reading about the electronic structure. It is written that when hydrogen's electron comes back to ground state from excited state, it releases energy in a specific amount according to Bohr. But ...
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0answers
45 views

Radius of $n^\rm{th}$ orbit of an atom in terms of Bohr's Radius

Bohr's Radius$=0.529$ Angstroms My book says that the radius of $nth$ orbit of any atom can be calculated by: $$r=n^2 a_o$$ where $a_o$ is Bohr's Radius. But I think it should be given by following ...
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0answers
49 views

I don't understand concept of excitation of atom (not electron)? [duplicate]

How does excitation takes place like we know about state of energy of electron and it's excitation to higher energy?? How does atom excite why is there atoms energy levels??
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1answer
128 views

$SO(4,2)$ symmetry of the hydrogen atom

The hydrogen atom with Hamiltonian obviously has $SO(3)$ symmetry since it just depends on the radius. $$ H = \frac{\mathbf{p}^2}{2m} - \frac{k}{r}$$ This is generated by angular momentum $\mathbf{L}...
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5answers
261 views

Is a heated tungsten filament in a “pure state” or a “mixed state”?

This question arose in the context of another discussion here: Semi-classical calculation gives wrong answer for emission I wanted to analyze the time-varying charge density of a heated tungsten ...
4
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1answer
114 views

How does Sisyphus cooling work in a photon picture?

Some years ago, during my masters degree, I took a short course on cold matter, which included a component on laser cooling and trapping taught by Ed Hinds. On the lecture on Sisyphus cooling, he ...
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1answer
92 views

Why “vacuum” in vacuum Rabi splitting (VRS)?

What is the role of "vacuum" in vacuum Rabi splitting (VRS)? Also, does VRS arise because of quantized nature of light? If not, what is a semiclassical explanation for VRS?
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2answers
114 views

How does absorption of light by atoms and molecules work?

I found this question on a hobby science forum (mainly about chemistry) and found embarrassingly that I couldn't answer the question. A few searches along the lines of 'photons absorption' here on Ph....
3
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1answer
71 views

Why does ionization energy increase with period for transition metals but not for the s and p blocks?

I noticed this the other day, and rather than go hunt in some atomic physics book I thought I'd post it here where the answer will hopefully be more useful to the wider internets. I was looking at ...
4
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3answers
148 views

How important is the Pauli exclusion principle in the distribution of particles on energy levels

It is usually said that the Pauli exclusion principle is the big arbiter of how particles will distribute themselves along energy levels (especially electrons on atomic orbitals), but how accurate is ...
3
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2answers
40 views

How exact does the wavelength of light have to be to be absorbed by an atom? [duplicate]

I have been reading sources such as this on absorption and emission which make statements such as: The interesting thing is that each atom will only absorb photons with exactly the right energy. ...
5
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1answer
107 views

Formation of a hydrogen atom from a proton and electron - detailed quantitative description

Suppose a region of empty space, to which we add one proton and one electron, initially separated by a distance on the order of centimeters, and as close to "at rest" in the center-of-mass frame as we ...
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2answers
37 views

Stimulated emission process in lasers, Is the atom making transition a correct statement?

I was studying the Lasers, there is a section on absorption and the author is giving the statement as "An atom in lower energy state E1 may absorb the incident photon and may be excited to E2 . This ...
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17 views

How do jj and ls coupling arise depending on the relative strength of the terms of a Hamiltonian?

Hamiltonian of two electrons orbiting nucleus in an atom is given by the equation: $$ H = \frac{p_1^2}{2m} + \frac{p_2^2}{2m} + V(r_1) + V(r_2) + \frac{e^2}{\left|\vec r_1 - \vec r_2\right|} + \xi (\...
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39 views

If 2 fermionic atoms form a molecule, will the molecule always behave as a boson?

2 fermionic atoms give a bosonic molecule. 2 bosonic atoms form a bosonic molecule. Is there a energy scale where these two molecules will behave differently? If yes, will it depend on the ...
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1answer
82 views

Is water boiling an excited state?

I was wondering and arguing (pro) with a friend that the process of water boiling is an excitation. I based my opinion on the theory that excitation is an increase in the energy level of an atom. I ...
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0answers
49 views

Hund's rules on wikipedia

I'm trying to understand the examples on Hund's rules on Wikipedia, but I have a problem. Wikipedia says that for Silicon the possible combinations of quantum numbers are $1D$, $3P$ and $1S$ (first ...
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2answers
32 views

Question on the Rydberg - Ritz Fromula

The question is to determine which of the following wavelengths $\lambda_1=7460nm$ $\lambda_2 = 4654nm$ $\lambda_3 = 4103nm$ $\lambda_4 = 3741 nm $ does not belong to hydrogen. My guess is that the ...
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2answers
1k views

Why do non-hydrogen atomic orbitals have the same degeneracy structure as hydrogen orbitals?

The solutions of the Schrödinger equation for hydrogen are the "electronic orbitals", shown in this picture: (source) They have the following degeneracy structure: (source) It is often said that ...
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1answer
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What is the meaning of this Feynman's statement? [closed]

Richard Feynman has a strange statement in first lecture of his known book "Feynman Lectures on Physics. He says If a piece of steel or a piece of salt, consisting of atoms one next to the other, ...
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1answer
50 views

Why do we have the absorption edge?

I am very puzzled by the discontinuity of any physical quantity. If the energy of the photon is smaller than the excitation energy of the atom, the absorption rate is zero; if the energy of the ...
3
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1answer
38 views

Is there a difference between typical spin-spin interaction and Fermi contact interaction from a mathematical point of view?

The reason for this question is that I have a paper that describes some interaction using the Fermi contact interaction in a classical form. I would like to study the same problem using quantum ...
1
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1answer
91 views

How does an Atoms electric field overcome an electrons inertia?

An electron has mass, and therefore has inertia. How does an atoms electric field perpetually overcome an electrons inertia, necessary to hold it in its shell? Does this require continual work to be ...
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0answers
47 views

Orbital magnetic moment of sodium atom

I've been struggling with understanding what determines the orbital magnetic moment of an atom. I have read online that for a sodium in ground state it is in fact zero, however i know that there exist ...
0
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2answers
42 views

Can electron capture occur with an external electron?

Can electron capture proceed with an electron not bound to the nucleus which decays (that is one that is bound to a neighboring atom, bound in a collective state like a conduction band, or free)?
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1answer
64 views

How to include temperature effect in optical bloch equations (optical pumping)?

My problem is about the optical pumping of Alkali atoms by circularly polarized pump light. Consider a circular polarized light ($\Delta m=+1$) $$\vec{E}(z,t)= \vec{E}^{(+)}_0 e^{-i\nu t}+c.c. $$ ...
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1answer
102 views

How many bits of information can be stored in an atom?

How many bits of information can be stored in an atom? The atom in question being as big as you like, but must be stable with regard to nuclear decay
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28 views

Moseley's law and value of effective nuclear charge

It's given in my book that $$\sqrt{\nu}=\sqrt{RC\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)}(Z-b)$$ The above equation is called Moseley's law $\nu$ is the frequency of X-ray emitted. $Z$is the ...
1
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2answers
72 views

How do I remove the negative sign from this derivation? [closed]

A homework problem required me to show that the first equation below can be written in the form of the second equation. It was all fairly simple except for the negative sign. I'm not sure how this is ...
0
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1answer
59 views

Cold Solid Matter at the End of a Black Hole's Acceleration Disk?

Is it possible that black holes magnetic field are rapidly cooling matter using a type of magneto caloric effect and cold fusion creating new matter only possible with a black hole's gravity? A type ...
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1answer
89 views

Bohr radius question [closed]

I'm doing a homework problem where it asks to calculate the diameter of a hydrogen atom with $n=600$. I used the equation $r=\frac{n^2a_0}{Z}$ where $a_0=0.529e^{-10}m$. Solving for $r$ yields: $$r=...
1
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2answers
47 views

Wavelength for imaging an ultracold atom?

I was reading Stamper-Kurn's article Experimental Methods in Ultracold Atomic Physics (link). In the imaging section (page 13), he mentions: Cold atoms are conventionally probed by optical imaging....
6
votes
1answer
258 views

If increasing applying energy to an atom excites electrons, why does electrical conductivity decrease as temperature increases?

Applying energy to an atom makes the electrons jump up to higher energy levels. This is known as excitation. Electrons on higher energy levels are easier to remove from an atom than those on lower ...
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0answers
35 views

Magnetic field of one electron

I want to reproduce a calculation of the magnetic field at the atomic nuclei produced by one electron in hydrogen: Maxwell gives us: $\vec \nabla \times \vec B = \mu_0 \vec j$ Doing the surface ...
5
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4answers
710 views

Why do electrons jump between orbitals? [duplicate]

When an electron is excited to higher energy levels, it will jump back to the same level from which it was excited. Why does it develop "sentiment" with that level?
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36 views

Why is Bohr's explanation called Bohr's model and not Bohr's theory?

I have seen an answer which tells the difference between model (specific) and a theory (general). And it makes sense 'coz Bohr explained it for the hydrogen atom only. But did he not make a set of ...
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2answers
87 views

Potential energy of a spherically symmetric charge density in a spherically symmetric electrostatic potential

I'm interested in calculating the potential energy of a spherically symmetric charge density in a spherically symmetric electrostatic potential. More specific, I'm currently trying to calculate the ...