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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86 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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2answers
70 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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1answer
642 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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1answer
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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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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0answers
43 views

How Light interacts with Atoms? [closed]

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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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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0answers
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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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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1answer
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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4answers
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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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1answer
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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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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1answer
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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1answer
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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1answer
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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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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1answer
41 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 ...
26
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5answers
6k views

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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0answers
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 ...
9
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0answers
36 views

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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1answer
98 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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0answers
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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1answer
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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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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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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10 views

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?
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2answers
773 views

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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1answer
56 views

Is there a way to strip all the electrons from single atom with atomic number greater than 2

Please explain by what means electrons extraction can be done. How person can focus activity on single atom (from precision point of view) to do so? How at each step person can know how much electrons ...
4
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1answer
101 views

How long does an electron stay on a given orbital?

Was wondering what the average time is for an electron on any given orbital, or how often they change energy levels. Thanks in advance.
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1answer
62 views

Why does most galaxies resemble a 2 dimensional plane? [duplicate]

Older galaxies mostly tend the revolve forming a disk. Why are the stars not revolving around the center of the galaxy like a sphere instead similar to electron in an atom?
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90 views

How to find the magnetic field due to a revolving electron of hydrogen atom in first orbit

So, I was thinking about the Bohr model of atom and I started to wonder how we could find the magnetic field due to a revolving electron (produced at the location of proton) of hydrogen atom in first ...
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2answers
37 views

What is the energy transformation in the fission reaction?

According to one of my physics textbooks, when U-235 absorbs a neutron it becomes unstable and soon fissions into two separate atoms. The forces driving these two atoms apart are electrostatic forces ...
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2answers
76 views

The counter-intuitive time scales in atomic physics and nuclear physics

Compare atomic physics and nuclear physics. The interaction in the latter is much stronger than that in the former. However, the typical spontaneous emission time scale in atomic physics is on the ...
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0answers
46 views

Derivation of Critical Mass of U-235

I am having trouble following an explanation of the critical mass of U-235 from my book (for high school physics). First off, every chain reaction of U-235 releases on average $\nu = 2.42$ neutrons. ...
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2answers
59 views

Energy released due to electrons transition

I came across this question in one of my physics books: Choose the correct answer: According to Bohr's model of the Hydrogen atom, the transition of an electron from n=2 to n=1 leads to release of ...
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0answers
66 views

Stark effect in Polonium and Plutonium

I found the following question given as an exercise in one lecture notes: What are differences between Stark effect in Polonium and Plutonium ? What are differences between Stark effect in light ...
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0answers
6 views

Why are these H cross sections given as a function of energy per amu?

The Atomic and Plasma-Material Interaction Data for Fusion Vol. 4 (1993) by the IAEA lists empirical fits for ionization and excitation of hydrogen by collisions with $\mathrm{H}^{+}$. The fits are ...
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1answer
27 views

selection rules and singlet state

In an introduction I read the following sentences: "In excited singlet states, the electron in the excited orbital is paired (by opposite spin) to the second electron in the ground-state orbital. ...
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2answers
73 views

An unknow atom has the shown energy levels

In an excersice i found, a supposed atom called fictitious (Fi) has the following energy levels: Then i´m asked: A) The energies of the emitted photons after a gas of Fi is bombarded with ...
1
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1answer
81 views

Is this incredible microscope technology real? [closed]

I recall reading about the relatively old invention of a microscope-like device; apparently able to zoom much further (and with greater clarity) than more "advanced" modern technology. I don't recall ...
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0answers
15 views

What is exactly the difference between an active and passive frequency standard?

In the case of passive atomic frequency standard, we take an atomic reference which has a resonant frequency response centered at certain particular frequency. Then we take a local oscillator and tune ...
0
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1answer
26 views

Can a magnetic field speed molecules up?

I heard somewhere that If you add a magnetic field to atoms in a closed space you would speed them up. Similarly to heating them up. Is this true is so what the atom consists of for this to work?
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2answers
69 views

Is there a way to make atom move faster without heating them?

The more heat you add the faster the atom will move. This is something that is common knowledge. My question is it possible to make the atoms in let's say a gas move faster without adding heat of a ...
0
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1answer
51 views

Can/will a proton escape the nucleus when a force is applied? [closed]

Protons are contained within the nucleus of an atom. Protons carry a positive charge. With an electric field, we can exert a force on the proton. Is it possible for the proton to escape the nucleus? ...
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1answer
37 views

Does the one-electron cyclotron confirm the classical model?

Reading this short article one gets the impression that, after all, the classical description of the atom is not superseded: In the past, researchers have successfully used several different ...
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40 views

First order time-independent perturbation theory: How to practically calculate the perturbed wave-function

This is one of the problems that draws the line between academically learning something, and having to use it. While I learned the formulas relevant to this, I just want to make sure I'm using them ...
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2answers
43 views

Where is the periodic nature in the Cs atomic clock? [closed]

In case of pendulum clock,lets say one swing ticks one second..but what is the analogy in case of CAESIUM atomic clock? Is 9,192,631,770 ticks is equivalent to one tick in pendulum clock? And how we ...