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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Can AMO physics be applicable for space travel? [closed]

I know it sounds very stupid question. I am a Ph.D student currently working on the AMO physics (Quantum Optics). I recently saw articles about the Spacex, and I thought it is really amazing, and ...
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60 views

Why do some elements burn different colors? [duplicate]

I have a torch lighter and it makes a green color when the flame passes over the metal in the center. What on the molecular level would a flame change color although there is no difference in ...
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31 views

Which Hydrogen Emission Lines Appear First?

When a blackbody is heated, it radiates photons. At low temperatures, there isn't much radiation at high-energy end of the spectrum but as the temperature raises, high-energy radiation becomes ...
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64 views

Is there a simple man's perspective of Pauli’s exclusion principle [closed]

I've been pondering over a questions from a while. Please forgive me if I am being too naive. We all know that because of Pauli's exclusion principle no two electrons can populate one state. This ...
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2answers
69 views

Is the conservation of angular momentum violated in electron jumps from one orbital to another?

I don't really know any quantum mechanics. But in our class, we were introduced to Bohr's model of the atom with his postulate that the angular momentum of an electron in the $n$-th orbit is $\frac{nh}...
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1answer
140 views

Thomson scattering cross section: free electrons vs atoms

I am trying to find a reference for the Thomson scattering cross section difference between free electrons and atoms. I have always assumed that free electrons have a higher cross sections, but I can ...
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40 views

Derivation of Bohr model equations (1) in his original paper

My question is rather straightforward. In his original paper ("On the Constitution of Atoms and Molecules") Bohr provides equations (1) for the frequency and major axis orbit: \begin{align} \omega &...
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1answer
73 views

Collision with a stationary Hydrogen atom [closed]

Can some explain me what happens when an electron or neutron collides with stationary Hydrogen atom? What are conditions for elastic and inelastic condition? For example, how to tackle following ...
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1answer
55 views

Free electron Gas shortcomings

I am studying surface states and the Rashba effect. A common model I keep coming across is to implement the free electron model. In this model we get the spin orbit interaction Hamiltonian by ...
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1answer
96 views

Smallest thing ever measured and quantum mechanic bs [closed]

Is it possible to prove in 2016 that the universe is made up of more discrete units than say an atom or quark? What is the smallest thing we have been able to measure, like not theorize about, but ...
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44 views

Can 2 photons make up the same colour as another photon?

So, my question deals with the excited electron shown above. (1st diagram) This electron can return to its ground state by either of two ways. One of the ways involves the emission of 2 photons. (2nd ...
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1answer
27 views

Why is there a difference in the formulas of emission spectrum wavelength in Bohr model and in X-Ray emission?

The wavelength of emitted radiation when an electron jumps orbits in the Bohr atomic model is given by 1/$\lambda$ = $R_H$ ($\frac{1}{n_f^2}$ - $\frac{1}{n_i^2}$) $Z^2$ But that of X-Ray ...
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35 views

Do any elements form stable doubly-charged negative ions?

It is perfectly possible for an atom - particularly on the electronegative end of the periodic table to form negatively-charged ions by attracting an electron, and these species can be stable, ...
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105 views

Stimulated Emission in QED

The explanations of stimulated emission which I have found all describe the phenomenon in terms of non-relativistic quantum mechanics. How might you describe it in a field theory such as QED? In ...
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20 views

How to calculate term symbols and quantum numbers in spectroscopic physics?

I am studying for an exam in Quantum and Atomic Physics, and I having trouble working out what all of the possible term symbols are for a given electron configuration. So for instance, if I have the ...
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1answer
35 views

How does one determine orbital configurations in multi-electron atoms?

When we measure absorption/emission spectra for hydrogen-like atoms, we can point to a particular line/energy level and say "Aha! That's almost exactly the $A\rightarrow B$ transition that we ...
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26 views

What does 'fully excited' actually mean?

In statistical mechanics you often hear the phrases such as 'when the degrees of freedom are fully excited then....'. An example would be the validity of the equipartition theorem. But what is the ...
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9 views

Charge distribution parametres

I'm reading an article regarding charge distribution parametres in muonic atoms ad I'm stuck in the very first pages. In particular, I don't understand, given a 2-parametre Fermi charge distribution ...
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1answer
42 views

Atomic Structure of Liquids! [closed]

Reframe: Liquids have a molecular arrangement less dense than that of solids. The liquid molecules are not stuck to each other like those of the solids. So my question is what lies in these spaces ...
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2answers
37 views

Photoelectric effect and wave particle duality

In a vacuum, if electrons are accelerated by a certain voltage, giving the electrons a specific de Broglie wavelength and were incident on a piece of metal, providing the wavelength was roughly the ...
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0answers
9 views

What is the growth mode of thermal-evaporated aluminum on organic subtrates?

Does aluminum grow in an island mode or layer-by-layer mode on organic substrates which is amorphous? For example, on PMMA, fullerene or surfactant thin films. Can I predict the mode by comparing the ...
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40 views

Singlet and triplet excited states in He atom

I found the following example for Term symbol usage in my coursebook: There are two electrons in He atom. Let the first one $e_{1}$ be in ground state, with $n_{1}=1$, $l_{1}=0$, $m_{l1}=0$, $m_{s1}...
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1answer
41 views

Why don't stars re-emit the photons they absorb, thus restoring a continuous emission spectrum?

If you shine white light through a gas, electrons can absorb sufficiently energetic photons to reach higher excited states. This produces gaps in the spectrum and it's how Helium was discovered. So ...
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96 views

Atomic Clocks: How is time measured?

I am trying to understand atomic clocks better. I am not getting HOW the cesium oscillation is actually being counted. So from my understanding of an older atomic clock: cesium gets heated-> ...
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14 views

Resonance Fluorescence spectrum of a symmetric state of two atoms

So recently I've learned about the fluorescence spectrum of an atom (say a two level system) driven by a laser close to its resonance frequency. You get a dressing of the atom states with the laser, ...
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1answer
66 views

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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17 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 ...
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1answer
39 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
302 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
37 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
28 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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47 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
68 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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83 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 ...
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1answer
92 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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142 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
22 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
44 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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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
122 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
259 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
112 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 ...
1
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1answer
65 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
106 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
68 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 ...
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3answers
145 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 ...
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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. ...
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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 ...