Questions tagged [atomic-physics]

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, unless otherwise stated, for the purposes of this discussion it should be assumed that the term atom includes ions.

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, unless otherwise stated, for the purposes of this discussion it should be assumed that the term atom includes ions.

Atomic physics always considers atoms in isolation. Atomic models will consist of a single nucleus that may be surrounded by one or more bound electrons. It is not concerned with the formation of molecules (although much of the physics is identical), nor does it examine atoms in a solid state as condensed matter. It is concerned with processes such as ionization and excitation by photons or collisions with atomic particles.

The term atomic physics is often associated with nuclear power and nuclear bombs, due to the synonymous use of atomic and nuclear in standard English. However, physicists distinguish between atomic physics — which deals with the atom as a system consisting of a nucleus and electrons — and nuclear physics, which considers atomic nuclei alone.

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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% empty space? I do not understand the mathematics…
Shades88
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What gives covalent bond its strength?

I came across the following passage from Structure and Properties chapter of Morrison-Boyd Organic Chemistry: What gives the covalent bond its strength? It is the increase in electrostatic attraction. In the isolated atoms, each electron is…
AVU
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Why is Mosely screening in heavy atom K-shell 1 unit?

The Wikipedia article on Moseley's law seems to show that the screening of heavy atoms is by 1 electron charge exactly (in the limit of large Z, experimental precision, within nonrelativistic limits, and). But why is this exactly one unit? The other…
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Is the photon energy required to cause an atomic transition $\Delta E+\Delta KE$, where $\Delta E$ is the "transition energy"?

An atom "at rest" can absorb a photon, and while some of this energy goes into increasing the energy level of the electron, momentum must be conserved, and so some energy must also increase the kinetic energy of the atom. The amount of $KE$…
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Recoil velocity of atom due to electron orbital change

If electron jumps from n =1 to n = 2 in hydrogen atom then how will we find recoil velocity of atom ( I am just beginner and had never crossed such question so can't understand where to start)
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Why does noble gas electron configuration have low energy?

In chemistry classes in primary school we learned that atoms "want" to reach noble gas configuration because it have low energy, so atoms on the left of the periodic table are willing to give away electrons to reach that state, while atoms on the…
Calmarius
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How were atom bombs made before the first atom was observed by electron microscope?

How were atom bombs made before the first atom was observed by electron microscope? Give a brief history regarding my question please?
Victor
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Is excited electrons life-time = half-life?

Everywhere I read something related to excited electrons in atoms I only see the word "lifetime". For example most excited states have a lifetime of a few nano to micro seconds and metastable states have a lifetime of a few miliseconds as far as I…
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Why can we only trap certain atoms?

This is a bit open ended, (and probably poorly asked,) but I've noticed that most experimental trapping only works for alkali metals. I know with my limited understanding of how a MOT works, that for MOTs we require that certain transitions be…
Jlee523
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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 $1\omega$ is produced. When the electron…
avikarto
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To what precision can people calculate the energy levels of oxygen or iron atoms?

For simple atoms like Hydrogen or Helium, the precision is very high now. But how about atoms like oxygen or even uranium? Could it be one in a million?
poisson
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Why are some transitions in an atom preferred more than others?

I read in my textbook (NCERT Textbook in Physics class 12, part 2, chapter 12, p. 432) that some emission lines are stronger than others, due to the preference of some transitions in an atom to others: While the Bohr’s model correctly predicts the…
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What's the longest time an electron can remain in excited state

When it is said an atom captures light, how long can the electron remain in excited state and is it holding some quantity of light between it and the nucleus?
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Is it possible to make a subatomic gap?

This was a bit hard to google due to lack of a distinct search term. What I mean is that while we can't make a physical construct that's thinner than one atom, I thought it might be possible to make a gap between two objects that is too small for…
Stylpe
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Is muonic hydrogen atom or exotic hydrogen atom more stable

According to Bohr's model of hydrogen atom, the energy of the electron is given by: $$E=\large-\frac{me⁴}{8εh²n²}$$ So if we replaced the electron with a muon whose mass is ~200me, will that new atom be more stable than usal hydrogen atom? Because…
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