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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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258 views

The term “Coherence” is overloaded!

I have troubles with modern terminology in the field of quantum information technologies. There are a lot of new terms that everyone is using and no-one takes time to explain, even though modern ...
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1answer
56 views

What is the largest wavelength of a photon that can excite an atom in it's groundstate?

Let's assume we have an atom in it's ground state. That atom interacts with a single photon and get's exicited to a higher energy level. How large can the wavelength of the photon be? I'm looking ...
5
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1answer
120 views

Photon creation and quantum field theory

I remember learning the following familiar story in high school chemistry class: "an atom consists of a nucleus of protons and neutrons, and a collection of electrons orbiting around the nucleus ...
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3answers
92 views

What is the largest wavelength that can excite an atom?

What is the largest wavelength that can excite an atom? Or is there even a largest wavelength?
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1answer
23 views

Can electrons jump between levels in same shell with constant $L$?

I see many cases where electrons jump from various energy levels of some $L$ value to various levels of other $L$ value. But is there any transition in same $L$ level between its different ...
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0answers
23 views

Optical deexcitation with energy higher than the excitation light?

Every line of the characteristic spectrum of an atom has not a perfectly defined energy (frequency), but a finite width (the higher the width, the shorter the lifetime of the excited state) right? ...
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2answers
1k views

What's the significance of the nickel crystal in the Davisson and Germer experiment?

Davisson and Germer, in 1927, conducted an successful experiment to prove the existence of matter waves. What's the meaning of using the nickel crystal? I mean, why didn't they use any other materials?...
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0answers
7 views

Excitation energies of optical transitions

If one speaks of the excitation energies of the three lowest optical transitions, does it mean that the first transition is HOMO -> LUMO and therefore the excitation energy $E_{LUMO}-E_{HOMO}$, the ...
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1answer
19 views

Number of Atoms [on hold]

I have some confusion regarding the past paper solutions, on atomic physics. So in my past paper solutions it states that the number of atoms in $1$kg of carbon is given by $=\frac{12\times 1000}{...
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2answers
24 views

Why does kinetic energy of elecron on Bohr's orbit not change if zero of potential energy changes?

If zero of potential energy is not taken at infinity, total energy and potential energy of electron change but not kinetic energy. Why is that so?
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1answer
30 views

What would happen if total energy of electron in bohr's orbit were positive?

I have read somewhere that if electron had positive total energy in orbit it would not follow a closed orbit. why is that so?
0
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1answer
28 views

Looking for a cheap, easy to find laser gain media? [closed]

So I want to make my own home made laser, but I'm having trouble deciding on what gain media to use. I'm not an expert on lasers but I know the basics of how they work from reading online. I want to ...
2
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1answer
50 views

Does an atom gain mass when it absorbs a photon?

I understand the at rest a photon has no mass, but it has energy. So when a photon is absorbed by an atom the atom gains the energy of the photon. This captured energy raises the mass of the atom by ...
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1answer
76 views

Is there a finite number to the possible state of electron in an atom?

Okay, I know you may say, there are infinite numbers of possible state of an electron between its ground state and ionic state, since energy levels get continuous as electron gets farther away from ...
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0answers
16 views

Why Mercury, Cadmium and Zinc has low melting and boiling points and elements next to them start melting at a bit higher temperatures?

I have been playing with online periodic table and noticed that melting/boiling points are lowest for noble gasses and non metals then it starts for metals on left and creeps from right side of the ...
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0answers
20 views

How to use Hund's third rule for excited electronic configurations?

Hund third rule states: For a given term, in an atom with outermost subshell half-filled or less, the level with the lowest value of the total angular momentum quantum number ${\displaystyle J\...
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7answers
4k views

Why do electrons absorb and re-emit photons?

Up to a certain time, I was told photons a.k.a. light was just a wave of energy. Then I was told, no, light is actually a particle. And electrons in an atom absorb and re-emit it. But why do electrons ...
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3answers
161 views

Newbie question: Atom identity. How can you talk about two electrons if electrons are identical? [closed]

How can you talk about two electrons if they are identical (indistinguible)? Does it make sense to let an electron to have an identity by itself? If they are on diferent places the place they are is ...
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1answer
67 views

Existence of isolated atom [closed]

Can a single atom be isolated (which is not possible yet) in space at far away distances? I have searched for it that an atom can only be isolated if there is no contact between that atom and other ...
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0answers
53 views

Doppler Cooling Limit Random Walk

In Foot's Atomic Physics, section 9.3.1 on the Doppler cooling limit, it uses a random walk argument to derive the mean square velocity from scattering to be: $\langle v^2_{spont} \rangle =\frac{1}{3} ...
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1answer
17 views

Cause and description of 'secondary' probability peaks in Above Threshold Ionization

While reading about above-threshold ionization, I found this graph on the wikipedia page about ATI: The $x$ axis represents the kinetic energy of the electron and the $y$ axis shows the ...
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0answers
32 views

Triplet states and the Hund's rule in identifying the ground state configuration (open shell)

I referred to some of the questions about Hund's rule on StackExchange, such as this for example, but still wasn't able to have my question resolved. (the wikiepdia page has $E_{ex} = C - \frac{1}{2}...
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1answer
50 views

Why are powdered silver and powdered platinum black?

The quantum-mechanical (relativistic) explanations for the observed colours of copper, silver & gold don't appear to explain the black colours of powdered silver (& powdered platinum). Can ...
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1answer
65 views

How do scientists experimentally (this means not theoretically) determine that an atom is not bonded with any other atom?

What I do not understand is how scientists can tell whether or not an atom is bonded to another atom or all by itself. If someone can help me understand this, please do.
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1answer
36 views

What are the types of infrared scattering?

There are various types of scattering of electromagnetic wave. what type of scattering involves infrared electromagnetic wave?
4
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1answer
48 views

Why do electrons fall into the nucleus in Rutherford's model of the atom but not in Bohr's model?

In Rutherford's atomic model, an atom's nucleus can't survive because of the electromagnetic theory of Maxwell. But in Bohr's model it can survive. My question is: in both atomic models, electrons ...
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1answer
35 views

Concerning the passage of light through a glass medium and it's apparent re-acceleration, is the absorption explanation supported by evidence? [duplicate]

When someone questions how light can re-accelerate after slowing down in a glass medium, the common answer is that it never really slows down, it is absorbed by the atoms and then released. Have ...
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0answers
21 views

Determine the fine structure constants

I have a little trouble in determining the fine structure constant given relative intensities and wavenumbers. A Ca spectrum shows the resolved 3d4s 3D - 3d4p 3D multiplet. The wavenumbers and their ...
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1answer
44 views

How electrons really revolve around nucleus through nodal plane in $p$ orbital? [duplicate]

I have read somewhere that electrons revolve around the nucleus and electrons are most probably found in orbitals. Can someone explain how electrons really revolve around nucleus through nodal plane ...
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2answers
72 views

Bohr quantization hypothesis [closed]

To explain Rydberg formula, Bohr have assumed somewhat general hypothesis which is applicable to various classical system. As far as I know he assumed that for any classical system with periodic ...
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1answer
53 views

Reflection of a ray of light [duplicate]

My question may seem small but I request all the readers to answer it deeply. When a beam of light fall on an object (not a black body), it gets reflected. The question is: What happens to the atoms ...
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votes
1answer
68 views

Seeing images in mirrors [duplicate]

As I know, when photons hit the surface of a mirror, atoms on the surface of the mirror are excited and when they back to some lower states, they emit photons. I have two questions about this process. ...
5
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4answers
195 views

Why does an atom in an oscillating electric field behave like an electric dipole?

How can I understand that an atom subjected to an oscillating electric field (e.g., $\vec{E}=\hat{i} E_0\cos\omega t$) behaves like an oscillating electric dipole? What is the underlying picture that ...
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1answer
48 views

What is the typical life of a carbon atom? [closed]

What I mean by this question: Carbon is the basis of life on Earth. Life started several billion years ago and I suppose that the majority of carbon atoms was already on Earth back then. If I take ...
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1answer
45 views

Selection rules for atomic emission: why doesn't the photon carry orbital angular momentum

The standard treatment of light-matter interaction is often accompanied by a discussion of selection rules for electronic transitions via a dipole coupling $\hat r \cdot \vec E$ (see for example ...
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3answers
52 views

Ionization Energy Confusion

In my Barron's SAT Physics book, it states that ionization energy is equal to the absolute value of the ground state energy. This doesn't make sense to me because ionization energy is the minimum ...
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1answer
62 views

The classical electrodynamic atom

What methods have been used to rigorously prove that classical electrodynamics does not admit a robustly stable atom? The conclusion is often stated and I am aware of the standard responses such as ...
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0answers
57 views

Bohr's model : reason for quantized angular momentum? [duplicate]

I would like to know if there is a mathematical proof that supports and shows how Bohr was induced in his model , for the hydrogen atom , to assume that the angular momentum was a multitple integer of ...
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0answers
24 views

Bremsstrahlung Radiation and it interaction with the nucleus

Recently I have been reading up on Bremsstrahlung Radiation, and how it is generate in diagnostic x-rays. So as I understand as the electron is fired at a target, which in diagnostic x-rays is ...
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1answer
40 views

Estimating Nuclear Radius Through Closest Approach, Can't We Just Give The Alpha Particle Whatever Kinetic Energy We Want?

When you fire an alpha particle at a nucleus, the electrostatic forces repel each other, causing it to slow down to a stop before accelerating back in the opposite direction. So the initial kinetic ...
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2answers
70 views

If $2p$ is circular, why is $2p_x$ not circular and what does $x$ mean?

I was reading about atomic orbitals. From Bohr's model, electron orbitals are considered circular. But as I saw the sub-orbitals like $2p_x$, $3d_{x^2-y^2}$ I noticed something strange. These sub-...
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1answer
25 views

What would be the order of energies and wavelengths of photons emitted from different electronic transitions?

When an electron from fifth orbit falls down to first orbit, then it emits a photon of wavelength (lambda ) in Lyman region of spectrum. But if an electron jumps from fourth orbit or third orbit to ...
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1answer
50 views

How many selection rules are there in atomic physics?

How many selection rules are there in atomic physics and how should they be used? Sometimes selection rules are governed by $\Delta j=0,\pm 1$. Sometimes $\Delta m_l=0,\pm 1$ is used. Sometimes $\...
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1answer
43 views

Why does Jaynes Cummings not describe an atom in free space?

I'm a bit confused about the application of the Jaynes Cummings model and what exactly is meant by "one single mode": Usually, it is said that the Jaynes Cummings model describes a single atom in a ...
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0answers
11 views

Tabulated Emission Lines beyond NIST

It appears that when it comes to atomic lines, the most complete table is provided by the NIST website, which is, verbatim, based on the tables of Basic Atomic Spectroscopic Data Handbook authored by ...
0
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1answer
65 views

What is the relationship between excitation and resonance?

From Resonance (particle physics) - Wikipedia: In particle physics, a resonance is the peak located around a certain energy found in differential cross sections of scattering experiments. These ...
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0answers
33 views

What is the best book to learn about EM wave's interaction with electrons, atoms, molecules in QM level completely?

I am interested in this, I couldn't find a book which tells every detail about EM waves and particle interaction. I would like to have a book that can explain me very well the concepts in order to use ...
3
votes
1answer
41 views

Is there a material emitting light when changing phase?

I think a substance which emits light when it gets vaporized could have numerous applications, for example in display technology or in leakage detection. The only problem is: I'm struggling to find a ...
4
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0answers
21 views

Low energy limit of high harmonic generation

I understand where the high energy cutoff comes from in high harmonic generation, with $E_{max}\approx I_p+3U_p$. However, I do not understand how, in the harmonic spectrum, radiation of frequency $1\...
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1answer
44 views

What is the difference between north and south magnetic poles at the atomic level? [closed]

How does the electron spin affect the magnet property? And how do magnets work at the atomic level?