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 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
31 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
88 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 ...
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1answer
63 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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138 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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36 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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1answer
87 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
27 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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11 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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37 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
71 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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46 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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27 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
851 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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98 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, ...
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1answer
41 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 ...
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1answer
27 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 ...
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1answer
84 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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36 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 ...
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2answers
39 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
60 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
76 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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23 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 ...
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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 ...
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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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74 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: ...
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1answer
29 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 ...
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1answer
109 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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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
votes
4answers
648 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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0answers
31 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
70 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 ...
2
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1answer
50 views

Absorption of photon as particle by an electron

As the photon gets absorbed by the electron and goes to higher energy state, does the photon remains in the electron itself in some form (radiation energy), thereby increasing the mass of electron?
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76 views

Intensity - wavelength graph for X-ray

This is an intensisity vs. wavelength graph of X-ray emmision. The cut-off wavelength is the minimum wavelength of the X-ray emitted. But doesn't minimum wavelength correspond to maximum energy? ...
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43 views

Is there any well-defined, measurable atomic size?

Is there any well-defined, measurable size at the atomic scale? I was under the impression that the van der Waals radius was a good way of describing the size of an atom, but it turns out to be a ...
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2answers
50 views

Bohr's model and positronium

I was trying to get an order of magnitude estimate for the radii and energies of positronium using the Bohr's model. I did find a few places where they have used the reduced mass to replace the ...
2
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0answers
29 views

How precisely do we know the van der Waals radius of hydrogen?

I've found several sources that say the van der Waals radius of hydrogen is $120 pm$. How precisely do we know this number? What order of magnitude is the error on this measurement?
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0answers
65 views

Estimating temperature with Boltzmann relation with split emission lines

I'm trying to estimate the temperature of a plasma through the use of hydrogen lines, $H_{\alpha}$ and $H_{\beta}$ using the Boltzmann relation: $$ \frac{ n_{2} }{ n_{1} } = \frac{ g_{2} }{ g_{1} ...
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1answer
59 views

Internal energy + energy of electron

Internal energy of a system composed of molecules or atoms is the mean energy of all these particles in the system (energy as kinetic energy, potential energy etc..). But what I am seeing that we are ...
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1answer
108 views

What force keeps electrons in their orbitals and not collapse into the positively charged nucleus? [duplicate]

I know about quantum mechanical model of an atom and how electrons behave like a standing waves and there isn't any lower level energy available for electrons below ground state energy and energy ...
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37 views

Two-Photon Transitions

I'm reading these course notes on two-photon transitions at http://cua.mit.edu/8.421_S06/Chapter9.pdf But I can't understand why it looks like they do not allow for Autler-Townes splitting. In ...
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0answers
20 views

Does an electron's energy decrease while performing its motion? [duplicate]

While revolving around the nucleus if the electron's energy decreases then will it hit the nucleus and if it does what will happen?
3
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2answers
82 views

What is basic difference between photoelectric effect and Compton effect?

What is basic difference between photoelectric effect and Compton effect? In both case a photon hits a loosely bound electron So whats the difference? We get current in photoelectric effect but not in ...
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1answer
132 views

Derivation of the Rutherford scattering formula

I have been trying to look for a derivation of the Rutherford scattering formula from Hyperphysics, but cannot find one. It doesn't show up in the original paper How is this equation derived? ...
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4answers
105 views

What is meant by an excited atom?

I want to know how an atom is when it is excited. If an atom, due to collision of another fast moving atom, becomes fast moving as well, is that also an "excited state"?
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1answer
59 views

Energy of hydrogen atom - Schrodinger equation [closed]

The wavefunction of the electron in the hydrogen atom is $ k* exp(-r/a)$ (k is the normalization constant), but it does not take n into account, whereas the solution of Schrödinger's equation ...
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1answer
55 views

Z coordinate expectation value of the Hydrogen atom

I want to find $z-coordinate$ expectation value $\textbf{<z>}$ of the Hydrogen atom wave function $\psi_{1,0,0} = (\pi a^3_0)^{-1/2}e^{-r/a_0}$ in its ground state. I read in some text that ...
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50 views

Is the Fermi golden rule really accurate for calculating the life time of an atomic level?

In my impression, Fermi golden rule is routinely used in calculating the life time of an excited atomic level. But it is based on the first order perturbation theory, so it is not expected to be ...
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Can I get Magnesium into gas at room temperature?

This might sit squarely at the intersection of physics, chemistry, and quantum mechanics. I make gas discharge tubes. One color that evades me is green. Apparently Magnesium will do this, but I ...
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21 views

Coupling between angular momenta of particles conserve angular momentum of each particle?

Suppose there are two particles in angular momentum numbers $j_1$ and $j_2$ respectively. Suppose there is some interaction that couple together the particles' angular momenta. As there is no external ...