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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Linear diatomic lattice - Brillouin zone [on hold]

Consider a linear diatomic lattice. Show that the amplitude equations $$A[2 \mu - m \omega^2] = 2 \mu B \cos(ka/2)$$ and $$B[2 \mu - m \omega^2] = 2 \mu$ A\cos(ka/2)$$ at the Brillouin zone ...
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Would you please explain this statement please [on hold]

As the atoms of a material are brought closer together to form the crystal lattice structure, there is an interaction between atoms, which will result in the electrons of a particular shell of an atom ...
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116 views

Flaw in Einstein's explanation of the photoelectric effect?

The essence of Einstein's idea is like this: if a system is in some bound state with energy $-E_b$ with $E_b> 0$ (the threshold of the continuum band is taken as zero), and we drive the system ...
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32 views

Atomic transition involving two electrons

In the Helium-like Iron ion, Fe XXV, there is a transition from $1s2p$ to $2s^2$, and the energy of the two levels are measured as 6667.5686 eV and 13546.26 eV. It seems like this transition involves ...
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The mass/energy of an $H$-atom and the gravitational force between it and another particle of mass $m$

The gravitational force between an $H$-atom and another particle of mass $m$ will be given by Newton's law: $$F=\frac{GMm}{r^2}$$ The question is, what is $M$ here? I thought the answer would be ...
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3answers
82 views

Is it not impossible to see a single atom using visible light?

We see things because some light gets bounced off them, and this "bounced" light is due to electrons jumping from higher energy states to lower energy states. So is it really possible to see a single ...
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52 views

How to use Hartree-Fock for helium?

I am thinking of using Hartree-Fock approximation to calculate the ground state energy of helium. The ground state wave function must have a symmetric orbital wave function. But in HF we need a Slater ...
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1answer
68 views

Why do the radii decrease when we move left to right in the periodic table?

The explanation that I have heard states that when we move horizontally across the periodic table, the number of electrons increases leading to a greater force of attraction from the nucleus. For ...
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Textbook recommendation: Tools for AMO physics/many-body theory [duplicate]

I'm looking for a textbook on modern techniques in AMO physics. In particular, I'm looking for discussion of many-body effects like e.g. Feshbach resonances, BEC's and superfluids, cavity QED, maybe ...
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3answers
33 views

How does hydrogen emit radiations of diffrent wavelengths and still is called to have line spectrum?

Things have mixed up completely in my mind. Firstly Hydrogen is an element so it produces a line spectrum. But the famous Bohr model for the Hydrogen spectrum, confuses me about how different ...
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Does the shell structure really make sense for a high-Z atom?

The shell structure picture is based on the mean field approximation, which replaces the interaction between the electrons by some mean-field potential. For a high-Z atom, like Fe, or even Ur, is the ...
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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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53 views

Spectral lines and QM

In the various presentations I've seen so far in atomic physics of series such as the Balmer series, the wavelength of each spectral line is definite - but in QM, free particles have no definite ...
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25 views

energy changes in an accelarated electron

why doesn't the electron fall into the nucleus if it is emitting radiation (accelerating charge emit radiation) . i have come to know they emit E=h*frequency waves, or does it get any energy?
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How do we know $\psi$ depends on $n,l,m$

Regarding the separation of $\psi$ to an angular and radial part, why does each part have a specific dependence of the quantum numbers? How can Schrodinger equation describe a system just from its ...
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1answer
27 views

Fine Structure Correction

The fine structure correction is composed of the relativistic correction and spin-orbit coupling. The lowest-order relativistic correction to the Hamiltonian is $$ H_r' = -\frac{p^4}{8m^3c^2}$$ ...
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1answer
51 views

What is the correct theoretical formula of the Hyperfine transition of neutral hydrogen (21cm line)

I found two different expressions to express the energy split of the Hyperfine transition of neutral hydrogen (21 cm line, HI) that are not equivalent, imo. from Wolfram: $$\Delta\ E= ...
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41 views

Book recommendation for atomic & molecular physics

What are some books for a sophomore undergraduate about atomic & molecular physics?
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28 views

How is the formation of the first atoms related to the cosmic microwave background? [duplicate]

Common atoms formed when the universe finally got cool enough for electrons to bind with atomic nuclei around the year 380,000. From what I understand this shift in state from plasma to discrete atoms ...
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55 views

Can electromagnetic fields be used to deconstruct and reconstruct molecular bonds?

I was thinking one day and came up with a theory after reading about how scientists were studying anti-matter by using electro magnetic fields to separate matter from the anti-matter they made. It got ...
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1answer
103 views

Size of hydrogenic atoms

Positronium consists of an electron and a positron. By what factor is a positronium atom bigger than a hydrogen atom? The solution has been explained to me. The characteristic length when solving ...
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1answer
69 views

What do atoms really look like?

When considering the orbital model of the atom it seems like the shape of each orbital corresponds the shape that contains a volume such that there is a 90% chance of an electron being there. I also ...
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23 views

Measuring the coherence between degenerate atomic ground states [closed]

Given a 2-level atom with the degenerate ground state and excited state with $j_g =j_e =1/2$. Assume that initially the atom is prepared in pure state with all the population in its ground state. What ...
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4answers
111 views

Can an excited atom have multiple electrons in excited states?

For an excited atom, is it possible for the atom to be excited twice, having multiple electrons in higher energy levels than for the atom in its ground state? If it is indeed possible, what is the ...
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Why is the nucleus so small and why is the atom 99.999% empty space?

A nucleus consists of protons and neutrons. Both are extremely heavy compared to electrons. Then how come they are contained within an extremely tiny space? And why does the atom consist of 99.999% ...
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doppler cooling temperature limit

Wikipedia shows a heating effect that causes minimum temperature achievable in doppler cooling as: "The atom performs a random walk in momentum space with steps equal to the photon momentum due to ...
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Determining other energy levels from knowing just two excited states

Suppose you know just two energy levels, e.g. 3.6 eV and 4.6 eV, for an atom of unknown composition. Is this enough information to determine all excited states for the atom up to 18 eV?
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Why are atoms of the same element exactly the same?

Based on what we know about atomic structure all atoms have an electron density function which describes the uncertainty in the position of an electron. Thus theoretically 2 atoms of the same element ...
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1answer
77 views

Where does the energy within atoms come from?

Most kinds of energy I know about involve a finite measurement and are transferred. In other words, energy in the universe is finite and is not lost or gained but only transferred through space one ...
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3answers
47 views

Understanding spectral line of hyperfine transition

I was looking at the contents of the Pioneer Plaque and I pretty much understood everything that was there, but not the so-called "Hyperfine transition of neutral hydrogen". Looking mostly at ...
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36 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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1answer
23 views

Why is the atom loss rate enhanced at the Feshbach resonance?

At the Feshbach resonance, the scattering length is enhanced. But why is the atom loss also enhanced?
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Fermi's understanding of the Doppler effect

I am now reading the classic paper by Dicke, The Effect of Collisions upon the Doppler Width of Spectral Lines At the very beginning of the paper, Dicke said ''Quantum mechanically, the Doppler ...
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47 views

How does electron excitation work for the Bohr model with non hydrogen atoms?

I've seen a lot of explanations of electron excitation by photons in the Bohr model but they all use a hydrogen atom which only has one electron. How does the excitation work for atoms with more ...
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74 views

What evidence is there for quantum leaps?

I find this very strange that an electron can 'teleport' from one energy level to another. So what evidence suggests this?
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1answer
111 views

Why can't we run through walls like Harry Potter? [duplicate]

This is a very simple and stupid question but ever since I watched the first Harry Potter and saw Harry and his friends run through a wall at King's Cross Station I have wondered what keeps us from ...
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1answer
115 views

What is the most accurate experimental confirmation of Rutherford's $\sin^{-4}\phi/2$ law?

What is the most accurate experimental confirmation to date of Rutherford's $\sin^{-4}\phi/2$ law, where $\phi$ is the scattering angle?
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Lattice structure, Debye-Scherrer-Method

My question is: How can I find out what kind of lattice structure I have, with simply using the Debye-Scherrer method? One part of my exercise was to calculate the static structure factor for a fcc ...
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1answer
91 views

Orbital magnetic moment versus Biot-Savart law

In atomic physics, the fine structure of spectral lines assigned to atomic hydrogen has always been explained by considering an orbital magnetic moment of atomic electron. Still this concept is ...
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2answers
41 views

Is there such a thing as an interaction radius for molecules?

My question is about estimating the radius of influence between two molecules; picture some mixture, comprised of water, oxygen gas (in small concentrations) and a molecule we denote $G$. In the ...
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1answer
88 views

In how many possible ways can a photon be emitted?

I am currently studying atomic physics, and I encountered the question above. I am posting this question because I can't afford to move on with even the tiniest bit of uncertainty in my understanding ...
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Ritz Variational Method

I want to use the Ritz Variational method to find a good approximation ground state and ground state energy for the hydrogen atom. For that purpose I take two different ansatzes, do the machinery of ...
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40 views

How does an electron manage to constantly revolve around the nucleus of an atom forever? [duplicate]

When an electron revolves around the nucleus of an atom is it using any energy in doing so. If so, where does this energy come from and how does it be a constant source (the electron revolves ...
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1answer
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Need verification: Hamiltonian formulation states that an atom is bounded to an eigenenergy state due to opposing kinetic and potential energy

I received an explanation from someone who said that electrons in an atom are trapped in an eigenenergy state $E_n$ as per Hamiltonian mechanics is because the KE and PE of the atom balances ...
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2answers
342 views

Does the energy of ground and/or excited states have uncertainty?

In this question about absorption of continuous energies by discrete atom states, one of the reasons given to explain the width of spectral lines is the uncertainty principle (natural broadening): the ...
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1answer
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Electron orbitals and the circular membrane vibrations

I just stumbled across the fascinating analogy between electron orbitals and the fundamental waves of a circular membrane in Wikipedia. Now the weird and arbitrary looking orbitals don't look so ...
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1answer
112 views

Unknown magnetic moment of orthohydrogen

Conforming to present atomic physics, the two elementary particles in hydrogen atoms can have either parallel or antiparallel magnetic moments, and the energy differences between these two kinds of ...
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1answer
132 views

How did we come to know that electrons actually 'move' in an atom?

Rutherford's experiments confirmed the existence of light-weight electron clouds in a mostly empty atom, and that they occupy some space around the nucleus. What made us conclude that they can move? ...