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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Theoretical proof of the Bohr's postulates

It was proved in an experimental way that the energy of a photon equals $E = h \nu$ electrons radii satisfy the equation $mvr = n \hbar$ Is it possible to prove these properties in a theoretical ...
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Two questions about Variational Method of quantum mechanics

I have two question about variational method of quantum mechanics. Why we always find the ground state energy by this approach. Why not the other excited states? When we find the ground state energy ...
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Observation of gauge in artificial magnetic fields

In the ultracold atom community, an "artificial gauge field" or "artificial magnetic field" is a spatially varying hopping phase somehow engineered into the system, so that atoms hopping around an ...
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During transition of the electron from high to low energy state, is the photon released always of same energy?

Is it not possible that during transition of an electron from higher to lower energy state, it can release multiple photons of low energy instead of a single photon of the exact energy difference ...
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What does 'easily reversed' mean in the NIST spectral database? [closed]

Cross posted to http://engineering.stackexchange.com/q/3303/ I'm trying to do some processing of optical emission spectra from sputtering plasmas, and am confused by what NIST means by 'easily ...
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Having trouble understanding spectral lines

In my notes I wrote that Rutherford's model of the atom could not explain spectral lines, because that is what my textbook says. I'm not really sure about the details of spectral lines though. I know ...
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21 views

First few energy Levels in Iridium?

I've been learning a bit of x-ray spectra on the side. I know that Iridium has Z = 77, and I am trying to plot out the first 4 energy levels. I learnt that electrons are filled up as ...
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11 views

Hyperfine structure interval rule only obeyed approximately?

The hyperfine interaction is given by $\Delta E = A \langle I \cdot J \rangle = \frac{A}{2}\left[ F(F+1) - I(I+1) - J(J+1) \right]$. The interval rule is given by: $$ \frac{\Delta E_{F,F-1}}{\Delta ...
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Radial excitation and orbital-angular momentum excitation

Sorry. Just want to make sure, but what does radial excitation and orbital-angular excitation mean in the context of bound states? Just higher $n$ and $\ell$ quantum number?
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Is the 21cm line of hyperfine structure hydrogen an allowed transition?

The ground state of hydrogen is $^{2}S_{\frac{1}{2}}$ with nuclear spin $I=\frac{1}{2}$. The levels are split by $F=1,F=0$. By the rules of electric dipole transition, $\Delta l = \pm 1$. But in this ...
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Why do the size of gaps/energy between different energy levels of mercury Hg vary as it goes further away from the mercury atom?

In hydrogen, the gap is getting increasing smaller, this is understandable: there will not be as much energy released as it goes down, and as attraction gets weaker. But in mercury the ordering is ...
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Would Hund's rules still be valid if the electron had spin 3/2?

One of my homework assignments in atomic physics was the following: Given electrons had a Spin of $S = 3/2$, what would be the number of the first 4 noble gasses (complete shells)? The obvious ...
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41 views

Laser output below, just above and way above threshold?

I've been reading up on lasers recently and learnt that within the cavity while the laser light is amplified by the gain coefficient, it loses power due to transmission and absorption. Suppose the ...
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43 views

What is the difference between the phase in molecular orbitals and the actual complex phase component of the wave function?

You often see in atomic and molecular physics texts that bonding occurs between two atomic orbitals when their wave functions are in phase. These pictures often depict the 'phase' as whether or not ...
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50 views

If 99% of an atom empty, and our body is made of atoms, does that mean 99% of our body is empty? [duplicate]

If 99% of an atom empty, and if we say that our body is made of atoms stacked together, then why is our body a solid object, rather than 99% hollow. I have one probable answer that I think might be ...
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1answer
68 views

Is this definition of orthohelium and parahelium incorrect?

"One electron is presumed to be in the ground state, the 1s state. An electron in an upper state can have spin antiparallel to the ground state electron ($S=0$, singlet state, parahelium) or ...
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91 views

How much space does an atom occupy? [closed]

So my stupid question is: we know that in the classical model of a atom there is a nucleus at the middle and electron revolving around it in orbits numbered from 0 to infinity. So according to this an ...
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When an atom is split, what form of energy is released?

When an atom is split, what form of energy is released? All of the websites I have looked at say there is a lot of energy released when an atom is split, but it never says what form of energy it is ...
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28 views

Slope of p-orbitals at the nucleus

Is there any analytic expression describing the slope of the p-orbital at the nucleus, for example for hydrogen.
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62 views

Driving $\sigma$ transition with light in superposition of $\pi_x$ and $\pi_y$ polarization of slightly different frequencies

Lets assume the following experiment. Circularly polarized laser light is sent through a Mach-Zender interferometer $\left(l_1 = l_2 \sim \,\mathrm{cm}\right)$ made up of polarizing beam splitters ...
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103 views

Why does Bohr's stationary orbits not radiate energy? [duplicate]

I am presently in high school trying to understand the Bohr's theory. I somewhat familiar with Maxwell's laws but very soon I'll learn about them thoroughly. So please could anyone explain with ...
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119 views

Electron energy in hydrogen

Is the energy of the electron in a random hydrogen atom in a superposition of all eigenvalues (some value upon measurement) or you will find it most likely in the ground state. I want to clarify my ...
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74 views

Is there experimental evidence for the model of discrete intervals and orbital distances for electrons around the atomic nucleus?

Is there strong supporting evidence of discrete electron shells or orbitals surrounding atomic nuclei? I realize the math works out and we have energy frequencies emitted, perhaps even atomic ...
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73 views

Basic concepts on Electricity [closed]

How do electrons move? I mean really do they move? I read that they move in circular shells AROUND THE NUCLEUS. How can they move in the conductor? I have read that there are valent electrons that ...
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Is there a word for all the particles in an atom?

That is to say, is there a word that picks out protons, neutrons, AND electrons, rather than just saying "nucleons plus electrons"?
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symmetry group of multi-electron atom

Neglecting spin effects, the energy levels of multi-electron atoms are characterized by states of definite total orbital ($L^2$) and spin angular momentum ($S^2$). From this it seems that the ...
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How does any vibrating object generate sound?

We all know that vibration is the cause of sound generation. But here my question is, Internally what happens in vibrating object which creates sound? I guess, generation of sound will be some where ...
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Radioactivity, alpha decay [duplicate]

In alpha decay, a $\text{He}$ nucleus is emited along with a daughter nuclide. Now suppose $\text{U}$ with atomic number 92 and atomic mass 238 emits an alpha particle and a daughter nuclide is formed ...
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Molecules from atoms [closed]

Why does two oxygen atoms combine to form a molecule and not 3 or 4?Also why does one sodium and one chlorine atom combine to form NaCl while two chlorine atoms are required to combine with one ...
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Question on heat

Is this statement correct? The oxygen and nitrogen molecules in a box has equal average kinetic energy but the oxygen molecules are faster. I am not sure because I thought oxygen molecules should move ...
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56 views

Complex scaling method for solving resonance states

I am now reading about the complex scaling method for solving resonance states. As far as I understand, the procedure goes like this: Let us take the 1d potential $V(x) = A e^{-x^2} x^2 $ as an ...
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96 views

What is nuclide notation referring to? Only the nucleus or the whole atom?

sorry that this is an easy question but I am just a bit confused about nuclide notation. When you say e.g. $^{240}_{94}\text{Pu}$, are you referring to the atom of $\text{Pu}$ or only its nucleus? It ...
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How is an atom ionized by electron impact?

Can someone walk me through in detail what happens when an atom is ionized by colliding with an electron? I would prefer a solid example so I can understand it more concretely. What I think:- -The ...
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55 views

What does excitation in an atom mean?

This is not regarding the definition of excitation itself. What I'm having trouble with is the difference between "electron excitation" and "atom excitation". When I electron inside the atom gets ...
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124 views

What happens when an electron collides with an atom?

I was solving this question: Here is part of the energy level diagram of hydrogen: n=4 --> -0.85eV n=3 --> -1.50eV n=2 --> -3.40eV n=1 --> -13.6eV When an electron of ...
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52 views

Energy transitions of 12.1eV electron?

Here is part of the energy level diagram of hydrogen: n=4 --> -0.85eV n=3 --> -1.50eV n=2 --> -3.40eV n=1 --> -13.6eV When an electron of energy 12.1eV collides with this ...
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91 views

Definition of “first excitation energy”?

I was solving a problem but I didn't know what the term "first excitation energy" means. The first excitation energy of the hydrogen atom is $10.2\text{eV}$. Calculate the speed of the slowest ...
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36 views

Sub-structure of hyperfine levels

In studying introductory atomic physics I have come across fine structure splittings in energy levels due to spin-orbit coupling. Which has a sub-structure called hyperfine structure which comes from ...
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Why is there no electric dipole term in the Hyperfine Hamiltonian?

I have been looking a several discussions of hyperfine structure. (For example: here and in the explanation for eq. 2.1 here It seems that the hyperfine interaction can be explained almost entirely ...
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110 views

Algebraic solution of Dirac equation for Coulomb potential

The Runge-Lenz operator enables an algebraic solution of Coulomb potential energy levels without a solution of a differential equation. What is the analog for the solution of the Dirac equation in a ...
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95 views

Are there unobservable, undiscovered atoms?

Is it possible that there is a network of atomic activity that our current scientific instrumentation cannot detect? In other words, could it be possible that there are unobservable, undiscovered ...
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About atomic transitions

I accomplished my homework but it opened a whole pandora's box of things I do not quite understand, so I would appreciate help. In x direction linearly polarized light excites atom transition from ...
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Understanding quantum coherence in biological processes (Magnetoreception)

Moved my questions to the top. Context below. Why is the strength of the electric field and the coupling constant being compared to the inverse coherence time? What is the inverse coherence time? Is ...
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1answer
39 views

How does Nitrogen transition between a quarter and a doublet state?

My degree was in Electrical Engineering, and as a result I don't fully understand the formatting of the ${}^4S_{3/2}$ ${}^2D_{3/2}$ and ${}^2P_{1/2}$ of the different 2p orbitals, and I don't believe ...
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Orbital angular momentum of electrons

In a QM class, to study the hydrogen atom, we started by defining the Hamiltonian $H$ for a central potential, then made an orbital angular momentum operator appear as part of $H$, then down the line ...
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45 views

what is a clock state?

What is a clock state in atomic physics ? I read this term here http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2708678/ and tried to find a reference to explain the same but have been unable to find this ...
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117 views

Can someone explain the quote “there would be no chemistry if electrons acted as bosons”?

I am reading a book and in a quote it says that if electrons acted as bosons, then all the electrons would occupy the lowest energy state, and there would be no chemistry. What does the author mean ...
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Database of experimental cross sections for atomic collisions

Does the atomic-physics community keep a comprehensive database of experimental data (cross sections) for atomic collisions? I am looking for data about Bremsstrahlung, ionization, elastic and ...
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Apparatus for generating plasma

I'm working on a project which involves superheating nitrogen to a state of plasma. I was considering using my Fusor, but this project has nothing to do with plasma, and I believe that there are way ...
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Is the Singlet state for Helium with 2 electrons symmetric rather than anti-symmetric as is meant to be for fermions?

I'm looking at two-electron Helium atoms where one electron is in the ground state (due to if it were in other states, it's de-excitation would simply lead to the ionization of the electron). The ...