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.

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Can electrons combine with neutrons to form negatively charged nuclei?

I've been wondering if electrons and protons could switch place such as constituent of an atom nuclei or that a proton "orbits" an electron instead ("inverted" hydrogen), are there forces on the quark ...
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Number of nodes in Hartree-Fock solution

The Hartree-Fock equation for atoms is of the form $\left[\frac{d}{dr^2}+f(r)-\epsilon\right]P(r)=g(r) \tag1$ Usually algorithms to solve this equation assumes that the number of nodes of $P(r)$, ...
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Interplay of energy between photon, electronic energy levels and kinetic energy

I can understand that atoms have quantized energy levels for its electrons, but an atom's translational kinetic energy is continuous. As such, why is the absoprtion spectrum not continuous? That is to ...
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How can one calculate spin polarizations for molecules?

it may be a simple question but I'm having trouble in this topic. For example, How can I calculate spin polarization values of molecules such as $CO$, $H_2$, $BeH$, $CsH$, etc.
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Why does bond vibration frequency depend on bond strength and atomic masses?

Why does a bond vibration frequency depend on the strength of the bond (does it relate to electrons shared in any way)? And why does it depend on the atomic masses of the atoms in the bond? I don't ...
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Energy of EM Fields in terms of Potentials

In reading the paper On the nature of the Hamiltonian for the interaction of radiation with atoms and molecules: (e/mc)p⋅A,−μ⋅E, and all that by E. A. Power, and T. Thirunamachandran (AJP, 1978), I ...
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Solving TDSE for molecular alignment

I'm doing my thesis, and I have to solve a TDSE for molecular alignment - non-adiabatic and non-resonant laser induce alignment. And I really need your help to solve it. I tried split operator method ...
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How Do You Find $K_\beta$ X-Ray Energy?

I know you can use Moseley's law to calculate $K_\alpha$ X-ray energy. Can this law be used to calculate the $K_\beta$ energy? $$ \Delta E = (-13.6eV)(Z-1)^2\left(\frac{1}{n_{1}^2}-\frac{1}{n_{2}^2}\...
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How to argue on physical grounds that a function is the ground state of a Hamiltonian?

$u_l(r) = Ar^{l+1}e^{-\kappa r}$ is provided as a solution to the radial wave equation for the Coulomb potential $$-\frac{\hbar^2}{2m}\frac{d^2}{dr^2}u_l(r)+\Bigl[\frac{\hbar^2}{2m}\frac{l(l+1)}{r^2} -...
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Electrons emitting photons. Real life example?

In highschool we are taught about Bohr's atom model and how electrons emit light/ photons when transitioning from a higher energy orbit to a lower energy orbit. First question Where does this ...
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Why are atomic electrostatic collisions perfectly elastic?

"In atomic or nuclear scattering, the collisions are typically elastic because the repulsive Coulomb force keeps the particles out of contact with each other" How does this allow the interaction to ...
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Photon absorption by free electron during Inverse bremsstrahlung: Why is a heavy particle needed?

I read about the process of inverse bremsstrahlung where a free electron can gain kinetic energy by absorbing a photon. However, I'm having some trouble to understand why exactly a heavy particle ...
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Compton effect for a moving electron

In a problem from Bransden and Joachain's Quantum Mechanics, it is asked to calculate the Compton wavelength shift, but the electron is now moving, with a momentum $P$, in the same direction as the ...
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Deutron bound state problem (2 body problem)

In deutron if we calculate the potential depth for just the bound case (that is, taking the binding energy as zero), we get the minimum potential depth $25 \; Mev$. But when we consider binding energy ...
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Contradiction between the results of calculation and the theoretical analysis of Stark effect

@Emilio Pisanty, in your explanation of the Stark effect on the furst excited state of Hydrogen, the electron cloud obtained by theoretical analysis shows that when the electric field is along the -z ...
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Why is only bandgap-energy usable? (Thermal Relaxation)

I know from solar cell physics, that in a first approximation, the maximum energy from an exited electron is the energy of the bandgap, no matter how high the electron was excited by a photon in the ...
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Ionization of solid materials

Is the ionization of solid material only theoretical or can it also be done in an expiriment? If yes then how?
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Coulomb's law (electrostatic force)

I have read about the electrostatic force so it is said that charges must be at rest, but in some exercises, the electrostatic force between the electron and the proton in an atom is calculated. These ...
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If a fluorescent atom absorbs UV and emits visible light, then how is energy conserved?

Light has a lower frequency than UV, so unless energy is also released in other forms, how can energy be conserved? What other forms is energy released as for fluorescence?
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Are specific energy levels the same distance away from the nucleus for all elements?

Atomic radius decreases across a period, but does this mean specific energy levels are different distances away from the nucleus for different elements (eg- the 2nd energy level)?
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How do we know not all photons are absorbed? Only those of specific energies?

When a photon hits an electron in an atom, its energy has to be equal to the difference in energy between the current shell and a shell with a higher energy level, otherwise it is not absorbed at all. ...
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1answer
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How do the electrons absorb energy in an discharge tube that is used for produce an emission spectrum?

When there's hydrogen in a discharged tube it produces an emission spectrum, emitting energy(photons). (Eg:-When an electron jumps from 3rd energy level to 1st energy level, the electron emits a ...
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Is the probability of an electron being somewhere zero?

So recently I've been reading "How to teach Quantum Mechanics to your Dog" by Chad Orzel. In chapter 3, he says, if I understood this right, that electrons can only exist in specific quanta - that is ...
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Number of electrons in an orbital

How do we know number of electrons per element since electrons do not have shape and volume? Isn't an electron just quantized fluctuating probability wavefunction? Is there an experimental study ...
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Ionizing materials [closed]

My question is pretty simple: Let's say I have an object composed of tow different substances. Is it possible to only ionize the particles of one of the two materials without also affecting the ...
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Can an isotope also be an ion?

In an element when the number of neutrons differs than that of protons, it is called an isotope. An ion is formed when an atom gains a net charge due to loss or gain of an electron.
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Why does the Bohr model give the correct energy levels for hydrogen even though it assumes a circular orbit?

I've been reading the answers for this question: Why did the Bohr Model Successfully calculate some of the energy levels in hydrogen? but it hasn't really satisfied my curiosity. Some answers suggest ...
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Hyperfine interaction and Thomas factor

The Hamiltonian of the hyperfine interaction is defined as \begin{equation}\label{eq1}\tag{1} \mathscr{H}_{\rm HFS} = -\boldsymbol{\mu}_I\cdot{\bf B} \end{equation} where $\boldsymbol{\mu}_I$ is the ...
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What are the Quasibound Molecular States

I have been reading several papers on Molecular Physics and I was wondering what are the quasibound molecular states. What do they differ from the ordinary molecular states?
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What next after Niels Bohr's model? [closed]

I'm in 9th grade,so I know Bohr's model. But it has many demerits: 1) It is against Heisenberg’s uncertainty principle 2) It cannot explain Zeeman and stark effect 3) No justification for his ...
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Is every chemical reaction a nuclear reaction?

This is a PhD-level question that I'm sorry to say is likely to annoy many a high school teacher or university professor trying to get their students to understand the difference between chemical and ...
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60 views

Why we use $p_x$ and $p_y$ orbitals?

The wavefunction of $2p$ orbitals with $m_l=\pm1$ have the form: $$\Psi_{p_{\pm1}}=\pm \frac{1}{\sqrt{2}}r\sin\theta\cdot e^{\pm i\phi}f(r)$$ We can make linear combinations and get the $p_x$ and $p_y$...
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Sommerfeld's Constant and Bohr's Quantisation Condition

I was solving a problem which had a different solution than what I found. This question doesn't emphasise on that problem but instead finds the motive for certain rearrangement in a formula:- ...
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Stability of plum pudding model

My textbook says that the plum pudding model(Thomson's model) should be electrostatically unstable. Why is that so?
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1answer
31 views

Can electrons be ionised with a wave below threshold frequency but infinite amplitude?

Electrons of a certain atom can only be ionised with a wave with frequency above a threshold. What if a wave's frequency was below the threshold but it had infinite amplitude? Because even though ...
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Electron absorbtion properties of ink

This idea has been in my mind for a while now but I can't seem to get any answers and that's mainly because of my limited theoretical background. My question is the following: **Would it be possible ...
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1answer
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Atom-electron interaction in an x ray tube

My question has to do with the absorption of an electron by an atom. When an electron approaches the atom there are two possibilities. Either the electron will do a "slingshot" around the nucleus (...
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1answer
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Electromagnetic radiation emission

Does Bremsstrahlung radiation produce only a certain type of electromagnetic radiation (for example X-ray) or can it also produce visible light when the trajectory of the incoming electron is not ...
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Electron absorbtion properties

Is it possible to predict the wave length of the electromagnetic radiation that will be emitted by a material when hit by a beam of electrons?
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Calculation of atomic spectrum

I need to calculate spectrum of Hg atom (wavelength and transition intensity), taking into account relativistic corrections. Can someone suggest a software or a package for atomic spectroscopy, that I ...
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Hirshfeld partitioning of the electron density

What is the theoretical background of the Hirshfeld partitioning of the electron density in simple terms? I checked many sources but could not find any good explanation.
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Physical explanation of spin-orbit interaction in many-electron atoms & nuclei

The electron of a hydrogen atom or any hydrogenic ion sees an internal magnetic field $\vec{B}_{\rm int}$ due to the proton or the nucleus in relative motion w.r.t the electron. The spin magnetic ...
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Clarification on the notation of a paper about hybrid

Here is a screenshot from this paper by J. P. Foster and F. Weinhold. This paper focuses on a model of hybridization. It therefore considers movement of electrons in three dimensions. The author does ...
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4answers
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Zero Angular momentum at a Non-Zero distance in Quantum Mechanics

In Bohr atomic theory We learn that only those orbits are possible for which angular momentum is intger multiple of $h$.ie. $$mvr=\frac{nh}{2\pi}$$ Here n is used for angular quantum number,That can ...
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1answer
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Electron density of filled vs unfilled orbital

I'm currently working on a project that involves calculating electron density maps of various orbitals, i.e. using radial and angular wave functions etc. and its got me thinking... Does the overall ...
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1answer
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Local and non-local interactions

When I look for the van der Waals interactions, they are defined as they are non-local interactions but no explanation for what they mean by non-locality. What would be the best way to understand this ...
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Approximate kinetic or potential energy of bound electron?

Is there some semi-empirical formula to estimate the average kinetic or potential energy of a bound electron in the $n$'th shell? Maybe some kind of a scaled & screened hydrogenic approach or ...
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How to add spin-polarization to an atomic DFT calculation?

I wrote a simple program to calculate the ground state total energy of isolated atoms with a density-functional theory approach. I took a similar approach as can be found here: certik/dftatom ...
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What is the advantage of neutral atom quantum network advantage?

I'm interested in quantum network system using neutral atom for my interest of atomic physics. But I'm curious about what the advantage of the neutral-atom-based quantum network instead of other ...
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Why will the number of neutron higher than the number of proton in the most of atom? [duplicate]

The chinese website said : In the most of atom,the number of neutron higher than the number of proton Does anyone know the reason?just explain it in easier way, Or does anyone know if the number ...

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