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, ...

learn more… | top users | synonyms (3)

0
votes
0answers
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 ...
1
vote
1answer
40 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 ...
0
votes
2answers
32 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 ...
0
votes
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 ...
0
votes
0answers
36 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 $n_{1}=1$, $l_{1}=0$, $m_{l1}=0$, ...
1
vote
1answer
39 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 ...
1
vote
2answers
86 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-> ...
0
votes
0answers
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, ...
6
votes
1answer
60 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 ...
0
votes
0answers
16 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
votes
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 ...
2
votes
3answers
299 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 ...
0
votes
1answer
33 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 ...
0
votes
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 ...
0
votes
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, ...
5
votes
0answers
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?
0
votes
1answer
44 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?
2
votes
2answers
63 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 ...
0
votes
2answers
72 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
votes
1answer
71 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?
3
votes
2answers
132 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, ...
1
vote
1answer
21 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 ...
1
vote
0answers
40 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 ...
0
votes
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??
4
votes
1answer
110 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 ...
1
vote
5answers
252 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
votes
1answer
97 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
vote
1answer
37 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?
0
votes
2answers
99 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 ...
3
votes
1answer
67 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
votes
3answers
142 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
votes
2answers
37 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
votes
1answer
93 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 ...
0
votes
2answers
30 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 ...
0
votes
0answers
12 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 ...
3
votes
0answers
38 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 ...
1
vote
1answer
74 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 ...
0
votes
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 ...
0
votes
2answers
31 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 ...
18
votes
2answers
912 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 ...
-2
votes
1answer
103 views

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, ...
1
vote
1answer
46 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
votes
1answer
31 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
vote
1answer
86 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 ...
0
votes
0answers
42 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
votes
2answers
41 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)?
1
vote
1answer
61 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 ($\Delta m=+1$) $$\vec{E}(z,t)= \vec{E}^{(+)}_0 e^{-i\nu t}+c.c. $$ ...
1
vote
1answer
80 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
1
vote
0answers
26 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
vote
2answers
71 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 ...