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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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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2answers
71 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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1answer
20 views

Can a particle accelerator really be constructed which can actually change the properties of a material (create a new kind of atom)? [on hold]

Can a particle accelerator really be constructed which can actually change the properties of a material (create a new kind of atom)? If not, what are some ways to create or synthesize a new atomic ...
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3answers
28 views

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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1answer
16 views

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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1answer
19 views

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 ...
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11 views

Equilibrium bond length (unit conversion problem)

For partially deuterated, diatomic hydrogen molecule I have a rotational constant calculated from rotational transitions in the molecule (transitions were given in $cm^{-1}$). $ B ≈ 44.4cm^{-1}$ I ...
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1answer
6 views

What happens to the velocity map image if the plane of polarization is not on the plane of the detector?

In an electron Velocity Map Imaging (in Velocity Map Imaging in general) it is required that the plane of polarization to be parallel to the plane of the detector (in other words, plane or ...
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1answer
19 views

Since electron clouds of different atoms repel each other, does that mean that touch is the feeling of electromagnetic repulsion? [duplicate]

Also when we rest our hand on an object does that mean we are effectively levitating because of the repulsion of the electron clouds?
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Atomic physics, determining levels and terms

In atomic physics I understand there a configurations, terms and levels. I think levels for instance appear because of spin-orbit interactions, so that terms are split. But I'm confused about the ...
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1answer
49 views

Why is it necessary to supply constant electricity to make a laser work?

As we know that in lasers there are excited atoms. When energy is provided in the form of light, heat or electricity to these atoms, these excited atoms after sometime go to a lower state of energy ...
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27 views

What is the largest atom with a reliable configuration-interaction (CI) calculation?

The simplest approximation for calculating the ground state of an atom is the Hartree-Fock approximation. To get accurate result for the ground state energy, one has to do configuration-interaction ...
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29 views

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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17 views

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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2answers
58 views

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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38 views

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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34 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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1answer
19 views

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 ...
2
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1answer
57 views

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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62 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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1answer
43 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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2answers
142 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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1answer
58 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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413 views

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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1answer
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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1answer
28 views

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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32 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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2answers
781 views

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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1answer
52 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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2answers
77 views

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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1answer
35 views

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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1answer
40 views

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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3answers
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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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2answers
122 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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1answer
35 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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1answer
30 views

Excitation energy of carotene using the particle in a box model

I'm practicing for an exam and I came across the following question: The linear, conjugated π-electron system of a carotene molecule comprises 11 atoms and the distance between two atoms is 1.4 Å. ...
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2answers
49 views

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
95 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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2answers
63 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 ...
2
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1answer
83 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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21 views

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
37 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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