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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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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1answer
35 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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0answers
15 views

How do you state the quantized radial acceleration of an orbiting electron? [on hold]

Assuming that each electron in the orbit around the atomic nucleus possesses the radial acceleration, is it feasible to write down the statement that the radial acceleration is quantized?
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43 views

What are the reactions that take place inside battery at the quantum level? [on hold]

I was just studying about how a battery works on the internet and found out that there are reactions of chemicals which make the electrons move. But what exactly happens inside a battery (lets take a ...
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1answer
136 views

Thermionic emission, delayed emission and predissociation

In molecular photodissociation, the thermionic emission, delayed emission and predissociation are the same? Otherwise, what is the difference between them? My question is not about the solids, but I ...
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0answers
27 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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0answers
54 views

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

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 ...
2
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1answer
110 views

Would Hund's rules still be valid if the electron had spin 3/2?

One of my homework assignments in atomic physics was the following: Given electrons had a Spin of $S = 3/2$, what would be the number of the first 4 noble gasses (complete shells)? The obvious ...
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2answers
64 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 ...
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0answers
22 views

The possible atomic term symbols for electron configuration of $3p^1 3d^1$ [closed]

An atom has an excited electron configuration of $3p^1 3d^1$. What are the possible atomic term symbols for this electron configuration?
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2answers
69 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 ...
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0answers
38 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
38 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
32 views

Stark broadening and Voigt fitting

I have LIBS spectral data acquired with a CT spectrometer of resolution 0.4nm. I fitted the Voigt profile into the spectral peak at $\lambda_0$. The lorentz $\Delta \lambda_L$ and the gaussian ...
3
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1answer
47 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
82 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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0answers
40 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. ...
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1answer
25 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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1answer
4k views

Why do the radii decrease when we move left to right in the periodic table?

The explanation that I have heard states that when we move horizontally across the periodic table, the number of electrons increases leading to a greater force of attraction from the nucleus. For ...
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3answers
531 views

How do I find the average kinetic energy and average potential energy of a hydrogen electron in the ground state?

How do I find the average kinetic energy and average potential energy of a hydrogen electron in the ground state? In my modern physics class, we are wrapping up the 3D Schrödinger equation, and I am ...
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2answers
261 views

Why does the conjugated $\pi$ bond not violate the Pauli Exclusion Principle?

Let's look at the molecule 1,3 butadiene: $CH_2=CH-CH=CH_2$ and number the carbon atoms 1 to 4 from left to right. The bonds between 1 and 2 and between 3 and 4 are double bonds: each ...
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1answer
22 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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Why can't neutron emit Electromagnetic wave?

Even though proton and neutron have the same mass(approximately) why does only proton have +be charge? If electron and proton can emit electromagnetic fields around them then why can't neutron?
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78 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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1answer
39 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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0answers
15 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
32 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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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
145 views
1
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1answer
119 views

Excitation energy of carotene using the particle in a box model

I'm practicing for an exam and I came across the following question: The linear, conjugated π-electron system of a carotene molecule comprises 11 atoms and the distance between two atoms is 1.4 Å. ...
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2answers
31 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
8 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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0answers
31 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 $n_{1}=1$, $l_{1}=0$, $m_{l1}=0$, ...
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1answer
38 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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2answers
78 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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1answer
484 views

Wigner Threshold law in Photodetachment and Photoionization

I am writing this question here because I have a problem in understanding the Wigner Threshold law in Photodetachment and Photoionization. The Wigner Threshold Law is given by: $\sigma$=$E^{L+1/2}$. ...
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1answer
138 views

What is the correct theoretical formula of the Hyperfine transition of neutral hydrogen (21cm line)

I found two different expressions to express the energy split of the Hyperfine transition of neutral hydrogen (21 cm line, HI) that are not equivalent, imo. from Wolfram: $$\Delta\ E= ...
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0answers
10 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
331 views

Why is the orbital angular momentum of a pi electron along the axis of two atoms' molecule one?

I'm reading quantum chemistry. The book says that the orbital angular momentum of a $\pi$ electron along the symmetry axis of a molecule made up of two atoms is $\pm 1$. I think this is a primary ...
3
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1answer
137 views

Observation of gauge in artificial magnetic fields

In the ultracold atom community, an "artificial gauge field" or "artificial magnetic field" is a spatially varying hopping phase somehow engineered into the system, so that atoms hopping around an ...
6
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1answer
58 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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0answers
13 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 ...
2
votes
3answers
292 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
36 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 ...
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0answers
94 views

If electrons are Bosons? [closed]

Electrons are spin 1/2 - Fermions. What would be the effect on atoms if electrons were either scalar(spin-0) or vector(spin-1) Bosons instead?
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1answer
30 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 ...
2
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1answer
222 views

Total magnetic moment in an atom

I have a doubt regarding the calculation of total angular momentum of electron in an atom. Which is the right way to do it? Method 1: Total magnetic moment $$ \begin{align} \vec{\mu_J} &= ...
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1answer
26 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, ...