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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About sub-atomic physics and the models used

I sit true every sub-atomic particle can have a mathematical representation as a wave? Can an electron and a proton and a neutron be represented as waves? Regarding every theory about sub-atomic ...
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What happens when you use an electric field to match atom oscillations?

I've been thinking about this question for the last few days: "What happens when you either use an electric field or sound / light to match the frequency of the atomic lattice?" What would happen to ...
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Organisation in Periodic table [migrated]

Why We find big spaces left in the periods of the Periodic Table between H and He; Be and B, or Mg and Al? What is the logic of such organization of the periods?
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Bohr/De Broglie simplfied model - joining orbitals

I understand that Quantum Mechanics has taken over and fully explains this but I'm struggling to understand in terms of the old model. Bohr's model as modified by de Broglie suggested that orbits ...
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Are ultracold atoms only created by intelligent life?

Nature has particle accelerators that are far beyond our capacity, but occasionally I hear atomic physicists claim that they are able to make something that has never been formed in any natural ...
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32 views

Why is the water diamagnetic?

I checked using my permanent magnet that water is diamagnetic. But why is it like that? Does this have any important consequence for life?
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What happens to the nucleus energy when it decays?

When an atom decays into another atom, what happens to the potential energy of the nucleus ? I think it will get more negative because, in general, through fission and fusion an atom tries to get a ...
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Why is energy released during decay?

Why is energy released when an atom decays into another atom, even though no energy is added? What does the mass defect mean? Is it because a nucleus which decays is unstable (proton/neutron = 1)? ...
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56 views

How does quantum mechanics explain stability of electron orbitals? [duplicate]

According to classical physics, an electron orbiting the nucleus would emit electromagnetic radiation. Losing energy in that way, it would spiral into the nucleus and the atom would collapse. Quantum ...
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41 views

Why is the photoelectric absorption coefficient finite at the threshold frequency?

I mean the photoelectric effect of the hydrogen atom. It is weird. By the Fermi golden rule, the transition or absorption rate is proportional to the density of the final states. At threshold, the ...
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139 views

Binding energy of Helium and repulsion of protons

I've just done an exercise of computing the binding energy of Helium 4, which is around 27,43 MeV. Obviously the binding energy "compensates" for the repulsion between the protons due to their ...
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57 views

is it possible to confine an atom in a container

Is it possible to confine an atom in a container for an indeterminate period of time? A possibly better way of phrasing the question: is it possible to block an atom from passing through an object?
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Why aren't orbitals symmetric?

In an hydrogen-like atoms the orbitals are solutions to the Schrodinger equation suitable for the problem. They describe the regions where an electron can be found. So, why don't they have spherical ...
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86 views

Does O$^{2-}$ really exist?

In chemistry it is common sense that we have O$^{2-}$. But from a physical point of view, does O$^{2-}$ really exist as a negative ion? I mean, as an isolated ion. It is not apparent that a neutral ...
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Carbon 14 disintegration

When $\beta^-$ disintegration happens to a Carbon 14 atom, a neutron "turns into" a proton, and an electron is emitted. Therefore the result of the disintegration is a Nitrogen atom plus an electron ...
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34 views

mirror nuclei: accounting for the difference in mass between nuclei

I was wondering if anyone here could guide me in the right direction with respect to the following problem: two nuclei are considered mirror nuclei if interchanging the neutrons and protons turns one ...
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31 views

The Interior of A Nucleon

Just like, in a Bohr model, the atom has a particular structure, what is it like inside of a Nucleon? Like, are there particular ways the quarks are arranged, and what about the binding energy that ...
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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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51 views

2s orbital wavefunction has non-zero probability at $r=0$? [duplicate]

The wavefunction for an electron within a hydrogen atom in the $2s$ state has the following wavefunction: ...
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Selection rule $\Delta S=0$: Why does a photon not interact with an electrons spin?

When talking about selection rules in atomic physics, many books state that the photon interacts with the electrons angular momentum such that that $\Delta l=\pm 1$. Absorbed/emitted photons exchange ...
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Ignoring spin, what is its orbital magnetic moment of an electron in a hydrogen atom in the 2p orbital?

I know that a magnetic dipole moment is given by $$\mu=\frac e{2m}I$$ and that the angular momentum is $$\frac {m_jh}{2\pi}.$$ However, I have also seen that angular momentum $I$ is given by $$I=\frac ...
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Charge density of an atomic orbital

Chemistry textbooks on atomic orbitals typically start off with the concept of electrons (viewed as negatively charged point-particles) moving around the nucleus, attracted and bound by the Coulomb ...
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Is it possible that every single isotope is radioactive, and isotopes which we call stable are actually unstable but have an extremely long half-life?

I've read that tellurium-128 has an half-life of $2.2 \times 10^{24}$ years, much bigger than the age of the universe. So I've thought that maybe every single isotope of every single atom are ...
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Valence bond wavefunction of nitrogen

Could someone explain to me how one finds the valence bond wavefunction of an atom? Take nitrogen for example, I know both nitrogen molecules have a valence-electron configuration of 2s22p1x2p1y2p1z ...
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Why do lines in atomic spectra have thickness? (Bohr's Model)

Consider the atomic spectrum (absorption) of hydrogen. The Bohr's model postulates that there are only certain fixed orbits allowed in the atom. An atom will only be excited to a higher orbit, if ...
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How can 99% empty matter have solidity? [duplicate]

If a simple atom with electrons whizzing around constantly is 99% empty space, one would think any solid-looking matter was 99% empty space. How can 99% empty matter have solidity?
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Would you please explain this statement please [closed]

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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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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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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92 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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58 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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80 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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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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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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31 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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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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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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59 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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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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73 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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27 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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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 ...