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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71 views

How to use Heisenberg to explain atom cannot be at rest

In a Dutch national physics exam at the level just before entering university there was a question about a molecule HI: one atom hydrogen plus one atom iodine. Within the molecule, the hydrogen ...
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390 views

'The size of an atom' using Uncertainty Principle

Suppose we have a hydrogen atom, and measure the position of the electron; we must not be able to predict exactly where the electron will be, or the momentum spread will then turn out to be infinite. ...
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149 views

Compton Effect Explanation

Can someone brief me about Compton effect and why does this happen? I searched everywhere read a CERN article too but couldn't understand it.
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141 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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64 views

If orbital shells are just probability functions, why are quantum numbers only ever integers? [on hold]

Quantum numbers are supposed to denote every individual orbital. But if orbital shells are probability functions, then orbitals can't be definite, solid things. So in that case, there can be variation ...
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633 views

Confusion in a trick in solving an energy eigenfunction

Given a non-relativistic energy eigenfunction for a central potential $\left|\Phi \right>$ In solving relativistic hydrogen atom, one of the terms is $$ \left<\Phi\middle|\frac{e^2}{r}\middle|\...
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28 views

Angular Momentum of Closed Subshell

Suppose we have a state with $2\ell +1$ fermions all entirely in the subspace of hydrogen eigenfunctions with $n, \ell$ fixed. That is we have a state occupied by $2\ell +1$ fermions involving $\mid \...
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25 views

Corrections to the Bohr energies of Hydrogen [on hold]

Among fine structure, Hyperfine splitting and Lamb shift, why Hyperfine splitting is the smallest while Fine structure is the largest?
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535 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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What is a standing wave?

I'm a highschool sophomore, bear this is mind when answering this question, in other words, the answer doesn't need to be in total layman terms, but it should be understandable by an applied ...
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2answers
70 views

Why don't electrons moving around in a orbit produce electromagnetic waves in their natural state? [duplicate]

If moving electrons produce changing electric field, and if changing electric field produces magnetic field, every electron must produce an electromagnetic wave. This means an atom in its natural ...
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1answer
73 views

What is the physical meaning of the parameter of a Poisson distribution?

I have done a laboratory session at my university where I had to check that the disintegration of nucleii follows a Poisson distribution $$P(n)=\frac{\lambda^n}{n!} e^{-\lambda},$$ where $P(n)$ is ...
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Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
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43 views

How Light interacts with Atoms? [on hold]

I think I have confused myself about how light interacts with matter, would somebody be able to clear these questions up for me? How does an atom reflect light? Can an electron just essentially '...
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18 views

Intermolecular space and penetration [duplicate]

As all materials have intermolecular space then why don't water comes out from a glass full of water?
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202 views

Is fluorescence from a single atom/ion visible with the naked eye (e.g. in a strongly coupled trap or cavity)

I remember sitting in on a conference talk by a person (possibly Rainer Blatt) doing research with trapped ions (or single atoms strongly coupled to light in an optical cavity), and the person showed ...
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107 views

Does the spin of an electron change when transferred from one atom to another?

Some atoms form bonds when they are given energy to create an excited state.From what I have learnt, every electron is assigned a specific spin quantum number. What I am curious to know,is that, is ...
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355 views

Principle of Reflection on atomic level

The well observed phenomenon has besides several others has always been a fascination to me, we are well aware of several theories, experiments and practical applications of the well known phenomenon. ...
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41 views

Atom-photon interaction

When we describe interaction of atom with EM field, we consider the interaction term in Hamiltonian as follows $$ W(t) = -\frac{e}{2\mu c} (\hat{A} \hat{p} + \hat{p} \hat{A}) + \frac{e^2}{2\mu c^2} \...
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34 views

What is the lowest energy atomic transition ever detected and identified?

In this concise and insightful answer it was pointed out that atoms can have an extremely large (possibly infinite) number of bound excited states. The Rydberg formula represents a simple model for ...
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1answer
30 views

Which is larger, all known, bound nuclear energy levels, or known, bound atomic energy levels?

Both the atomic nucleus and the electrons are (complex) quantum systems and have large numbers of energy levels and transitions, and a basic shell model is usually part of introductory atomic physics ...
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46 views

relation between line width and life time

I don't see why the following relation should be correct. The scattering rate $R_s$ of atoms in a laser beam is $R_s=\frac{1}{T_s}$. $T_s$ is the time interval between the first and second ...
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52 views

What is the capacity of an electron to absorb energy? [closed]

When an electron get excited we find that electron absorbs energy and jumps to the required shell. This means that electron can absorb an infinite amount of energy and can get excited to infinity ...
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34 views

Expectation value of radius of hydrogen atom [closed]

As an excercise, I have to do the following: The hamiltonian of the hydrogen atom is given. Try to find the radial part $f(r)$ of the wavefunctions by assuming it to be a power series and show that ...
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24 views

Equivalent electrons, terms of atomic subshell

Let's say I consider $p^2$ case. For non-equivalent electrons it gives six possible terms: $\{^1S, ^1P, ^1D, ^3S, ^3P, ^3D\}$. When we consider equivalent electrons, Pauli principle, obviously ...
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276 views

What will happen if a ground state hydrogen atom is placed in a low frequency, but high intensity laser field?

Similar questions have been asked before, but this one extends the scope of interpretation and applications. Let us ask the question: What will happen if we have a laser gun that produces a high ...
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345 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 ...
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25 views

Emptiness of the atom [duplicate]

If the atom is actually 99.99% empty, why can't we just put our hands or things inside them?
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111 views

Symmetries of atomic orbitals, s-state forms a triplet!

I have a trouble understanding how s-subshell electrons can form a triplet state ever. In general isn't it true, that there are only two cases for s-state: $\ell=0$, $s=1/2$, $J=1/2$ - doublet (one ...
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If particles are points, then aren't atoms empty space?

Zero dimensional points do not take up space, so then wouldn't everything in the universe be literally empty? Or is there something that I'm missing?
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23 views

Using Bohr's postulate find the relation for electron velocity of lithium atom

Using Bohr's postulates derive formula for velocity of electron on 4th orbit in doubly ionized atom of lithium $_{3}Li^{7}$. Using $$mvr=n\hbar$$ and $$\frac{mv^2}{r}=\frac{1}{4\pi\epsilon_{0}}\frac{...
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113 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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39 views

π , σ - atomic transitions with respect to a quantization axis

In the absence of a magnetic field, how does one physically (i.e perhaps in a thought expt) access delta_m = 0 or +-1 transitions since (as I understand it) the choice of quantization axis is ...
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20 views

A good book on spectroscopy

I have found out that there are two kinds of books on spectroscopy: chemistry prospective experimental physics prospective I am looking for a book which contains more or less rigorous theoretical ...
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46 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....
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108 views

Crystal field in diamond

The crystal field effect occurs in ionic crystals and causes a splitting of the magnetic quantum levels of the cation. The magnitude of the splitting may be roughly computed by obtaining the potential ...
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75 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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Can AMO physics be applicable for space travel? [closed]

I know it sounds very stupid question. I am working on the AMO physics (Quantum Optics). I recently saw articles about the Spacex, and I thought it is really amazing, and thinking about the possible ...
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11 views

How do the magnetic moments of protons and neutrons effect the total magnetic moments of atoms?

I've heard that magnetic properties of atoms are mostly determined by the presence or absence of electrons with unpaired spin. The proton has a magnetic moment of $1.4 \times 10^{-26} J/T$ and the ...
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Are there exact analytical solutions to the electronic states of the hydrogen molecular ion $\mathrm H_2^+$?

The hydrogen molecular ion (a.k.a. dihydrogen cation) $\mathrm H_2^+$ is the simplest possible molecular system, and as such you'd hope to be able to make some leeway in solving it, but it turns out ...
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97 views

Alternate light and dark regions in cathode ray tube

There are a many alternate light and dark regions present in the cathode ray tube, as the pressure is reduced to minimum, like Crooke's dark space,negative glow, Faraday's dark space and at very low ...
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26 views

Selection rules for electric quadrupole radiation

The selection rules for electric quadrupole radiation in a Hydrogen-like atom are: $$ \begin{aligned} \Delta l &= 0,\pm2 \hspace{1cm}(l=0\leftrightarrow l'=0 \textrm{ is forbidden}) \\ \Delta m &...
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11 views

Specific microstate(s) corresponding to total angular momentum quantum number

Given a certain number of electrons in a certain electronic configuration (say, d$^2$ or (n$_1$p)(n$_2$d)), all combinations of the quantum numbers $m_l$ and $m_s$ can be constructed. Each of these ...
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37 views

Understanding Zeeman Splitting

I'm reading a standard modern physics history book ("Inward Bound" by A. Pais), and I realized I don't really understand Zeeman splitting well. In the section I'm reading, there's a short discussion ...
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Is it possible to “see” atoms?

As per my knowledge, atoms are small beyond our imaginations. But there is an image on Wikipedia that shows silicon atoms observed at the surface of silicon carbide crystals. The image: How can we ...
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How is the number of electrons in an atom found?

I was wondering, what type of experiments were held to identify the number of electrons in an atom? (For example, how do we say that carbon has 6 electrons and magnesium 12.) I would like someone to ...
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11 views

Do electronic energy levels of an atom effectively shift for scattering processes if the atom is moving in the lab frame?

When an electron of low energy scatters off an atom it interacts with one of the electrons in its shell and can transfer energy to it. The energy transfers would be discrete, since the shell electron ...
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What causes Potassium to decay into Argon the way it does

From evolutionwiki: "Potassium 40 decays into argon 40 through a process known as electron capture. In electron capture, an electron from the innermost electron shell "falls" into the nucleus, ...
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What can be the result of interaction of H- ion (2.1 MeV) and stationary H2+ ion?

I believe there is Coulomb scattering. However, are there any other channels? Could the products of the reaction be H and H2, and what would be the cross section of this reaction?