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, ...

learn more… | top users | synonyms (3)

2
votes
1answer
77 views

Is Neutronium possible?

Now I am not talking about neutron stars here. I am talking about a supposed substance with only neutrons in the nucleus. All atoms of this category would have a negative charge and negative charge ...
5
votes
1answer
84 views

What do term symbols with a half-integer “$L$” like $^3[3/2]_{1/2}$ mean?

Atomic term symbols are used to notate the angular momentum content of the electronic states of an atom, and are normally written down as $$^{2S+1}L_J$$ where the state has total spin $S$, spin ...
4
votes
0answers
40 views

Natural linewidth of hyperfine levels?

The D2 line of $^{87}Rb$ is the transition between the $5^2$$P_{3/2}$ and the $5^2$$S_{1/2}$ states. Its linewidth $\Gamma$ is always quoted to be $\sim 6 MHz$. But both states have hyperfine ...
3
votes
0answers
56 views

What is the physical meaning of the parameter of a Poisson distribution?

I have done a laboratory session at my university where I had to check that the disintegration of nucleii follows a Poisson distribution. $$P(n)=\frac{\lambda^n}{n!} e^{-\lambda}$$ Where $P(n)$ is ...
8
votes
2answers
169 views

Is this a correct demonstration for why elements above untriseptium cannot exist?

With the confirmation that elements 113, 115, 117, and 118 are indeed fundamental elements that are now to be named on the periodic table, the next question is: what is the highest atomic number ...
1
vote
1answer
60 views

Broadband light term in a Hamiltonian

In atomic systems, for a two-level system, the Hamiltonian can be written in the form: $$H=\left( \begin{array}{cc} E_1 & C_{12} \\ C_{21} & E_2 \\ \end{array} \right)$$ where $E_1$ and ...
2
votes
1answer
155 views

Hydrogen atom in superposition of energy eigenstates

Suppose a single hydrogen atom is in a superposition of energy eigenstates: $$ \psi = \frac{1}{\sqrt{2}}\psi_{100} + \frac{1}{\sqrt{2}}\psi_{200} \,.$$ Then energy will be $E = ...
1
vote
1answer
40 views

Minimum Power Required to Maintain a Population Inversion

According to many sources, the minimum power required to maintain a population N in the upper level of a two level laser system is $$P_{min}=fA_{21}Nh\nu$$ where $f$ accounts for the lack of 100% ...
1
vote
1answer
34 views

Stark broadening and Voigt fitting

I have LIBS spectral data acquired with a CT spectrometer of resolution 0.4nm. I fitted the Voigt profile into the spectral peak at $\lambda_0$. The lorentz $\Delta \lambda_L$ and the gaussian ...
1
vote
1answer
57 views

What is the conditions to excite an atom by collision?

I know that an atom can become excited in one of two ways: by absorbing some energy from a source of electromagnetic radiation or by colliding with some other particle—another atom, for example, but ...
1
vote
1answer
51 views

What is an object made of? [duplicate]

If object made of atoms and atoms are invisible then when we look at an object or touch an object what we see or feel?
1
vote
1answer
143 views

By what mechanism is a photon emitted or absorbed in atomic electron state transitions?

I understand atomic emission and absorption spectra well - photons of a specific energy can be emitted or absorbed by atoms, if that energy corresponds perfectly to the energy difference between two ...
6
votes
3answers
591 views

How can light emit three kinds of spectra?

In case of black-body radiation, radiation gives continuous spectra. Molecular spectra is an example of band spectra. Similarly, there's also the atomic spectra. Why are the spectra of light not same ...
0
votes
1answer
141 views

Fusion, Magnets and Quantum Generators [closed]

I cannot even play like I'm even at this level, but this is the fusion reactor in Germany called the Wendelstein 7-X stellarator. These doughnut-shaped magnets (often seen on Physic Exchange) are ...
1
vote
3answers
61 views

Are atoms elementary? [closed]

I'm reading wikipedia about Real neutral particle. I know, there are many different particles discovered in the background of atom, which was ( Neutrons + Protons + Electrons ) before. For example, ...
1
vote
1answer
49 views

Which electron is first ionized $n=2,\ell=1, m=?$ [closed]

Eletrons in atoms are described by n,l, m, s quantum numbers? For noble gas 1s2 2s2 2p6 which is the first electron that will be ionized n=2, l=1, m=?, s = ?
0
votes
0answers
39 views

Multi-photon excitation probability for a two-level system

If a two-level system with a lifetime $\tau$ is excited with a pulse of duration $t_{pulse}$, what is the probability of exciting more than one photon? For simplicity we can take it to be a $\alpha ...
0
votes
0answers
36 views

Oscillator Strength vs. Dipole Moment

I'm reading "Bose-Einstein Condensation in Dilute Gases" and, in the background chapter (on page 51), the authors introduce the idea of the oscillator strength for a particular transition. The ...
1
vote
1answer
32 views

Free space problem in matter [duplicate]

We know that atom is ninety nine percent empty and all matter is made up of matter then why matter is mostly empty ?
1
vote
0answers
29 views

Is the electron of carbon identical to that of hydrogen? How to prove it? [duplicate]

I am still confused with whether, for example, the electron of carbon is exactly identical to that of hydrogen. How can the scientist confirm this?
0
votes
0answers
35 views

What is $r$ in angular momentum quantization rule?

We know $$mvr= nh/2π $$ What is $r$ here if I consider positronium system. I suppose it should be the radius of the orbit in which both are moving. But when I take the above equation and electrostatic ...
5
votes
1answer
285 views

Are orbitals observable physical quantities in a many-electron setting?

Orbitals, both in their atomic and molecular incarnations, are immensely useful tools for analysing and understanding the electronic structure of atoms and molecules, and they provide the basis for a ...
1
vote
2answers
103 views

Laser cooling of atoms: more area or more power?

I want to optimise a Magneto-Optical trap. Laser beams come from the the x, y and z directions (positive and negative) and slow the atoms down. Would it be better to increase the beam spot-size ...
8
votes
2answers
169 views

What does an orbital mean in atoms with multiple electrons? What do the orbitals of Helium look like?

I am wondering about this. It is a familiar sight, the orbital diagrams for the hydrogen atom, depictions of which are abundant and so are not in need of reproduction here. However, what about the ...
0
votes
1answer
32 views

What is the reason behind the very high value of nuclear density? [closed]

I know how to arrive at the formula but I want to know it's such a huge number almost 2 X 1017 kg m-3, which is a huge number, all the more surprising to me is that it's a constant! Each and every ...
3
votes
1answer
84 views

Does the spin of an electron change when transferred from one atom to another?

Some atoms form bonds when they are given energy to create an excited state.From what I have learnt, every electron is assigned a specific spin quantum number. What I am curious to know,is that, is ...
7
votes
3answers
394 views

Can an electron gain energy by another electron?

Is it possible for an electron to gain energy from another electron which is jumping from higher energy level to lower energy level, and shifts to higher energy level?
0
votes
1answer
48 views

Does the proton wobble due to the electron's orbit in a Hydrogen atom?

In a hydrogen atom the nucleus only has one proton and no neutrons so the electron to nucleus radio is higher for hydrogen than that for any other atom. Does the orbiting electron induce a wobble on ...
3
votes
1answer
106 views

Are atoms unstable in 4+1 dimensions when quantum mechanics is taken into account?

I understand that in 3+1 dimensions according to classical physics atoms should be unstable however atoms are stable in 3+1 dimensions because the behavior of atoms is governed by quantum physics ...
1
vote
0answers
50 views

Can one measure experimentally the average distance between the two electrons in the excited state of helium in the singlet versus triplet states?

$\frac{1}{\lvert\ \vec(r_{1})-\vec(r_{2})\rvert}$ is a hermitian operator so I am supposing there could potentially be an observable with this which might be experimentally measured. We can measure ...
0
votes
0answers
8 views

Discrepancy of capture from 2p+1 state to 2p(+-1)

In the (nlm) characterization of hydrogenic orbitals. Consider the collisions H+ + H(2p+1) ---> H(2p-1) + H+ H+ + H(2p+1) ---> H(2p+1) + H+ where an electron capture has ocurred. Should the ...
1
vote
2answers
172 views

Possible inconsistency in Bohr atom model [closed]

It is well known that Bohr model is not totally right. But I recently discovered a very curious inconsistency (if I am right) which I haven't seen explained anywhere. The first postulate of Bohr ...
1
vote
1answer
50 views

The point of charge neutrality in the Hydrogen Atom

If we treat the Hydrogen Atom like the Bohr model then we have a proton in the center with an electron orbiting at some radius (the Bohr radius). In this picture you can imagine the electric field ...
0
votes
0answers
28 views

Bonding Two Cationic Hydrogen Isotopes (protium) yields H2 or He?

If you have two hydrogen atoms. And they are the isotope form "Protium" (1 neutron removed) and they are also cationized +1 (1 electron removed) then you have (in a sense) a single proton (two of them ...
1
vote
2answers
225 views

Can you breakdown an atom?

Protons, neutrons, and electrons make up the atom, but I've heard that you can't breakdown an atom. How do we know that the electrons, protons, and neutrons make up the atom without being able to ...
2
votes
1answer
161 views

Difference between photon upconversion and two photon absorption?

One can find in the wikipedia the following assertion: Upconversion should be distinguished from two-photon absorption However, it is difficult to tell the difference between both processes by ...
0
votes
0answers
105 views

Characteristic X Ray and Intensity-Wavelength Graph

This is somewhat the kind of graph given in my book. Questions- Q.1- Why is the intensity much higher for the characteristics rays than the continous spectrum? I understand that the wavelengths ...
0
votes
1answer
111 views

Proof for quantized angular momentum [duplicate]

In Bohr's model, Bohr stated that the angular momentum of the electron is quantized and stated that $$L=\frac{nh}{2\pi}$$ So what is the proof for that equation or, in other words, how did he derive ...
0
votes
1answer
49 views

The force applied by two charges on each other when there is another charge nearby them

QUESTION 1 Let me give two simple scene of charged particles to make you understand my question. There is a fixed positive charged particle in the center. Scenerio 1 : A fixed negative charged ...
0
votes
1answer
23 views

Cohesive energy per atom and energy of a single covalent bond

If I have the energy per atom $e=7.37 $eV, how can I estimate the energy of the single covalent bond in the diamond?
1
vote
0answers
62 views

Applying Bohr model on a system electron and positron [closed]

Consider a hypothetical particle consisting an electron and positron revolving around their common centre of mass. If the Bohr Model is applied on this particle, then find the value of Rydberg ...
2
votes
2answers
112 views

How do we decide whether an electron orbital has a non-zero or zero probability of lying inside the nucleus of an hydrogen atom?

How do we decide whether an electron orbital has a non-zero or zero probability of lying inside the nucleus of an hydrogen atom? It is mostly from the radial function, as to what I think but how ...
0
votes
1answer
39 views

The counterfactual possibility to explain discrete energies in Thomsons plumpudding model

In the german edition of "Tipler: Physics for scientists and engineers" there i a small text about the plum pudding model of the atom. i give a direct translation: "Thomsons plumpudding model of a ...
2
votes
2answers
50 views

When dihydrogen is formed, are photons being emitted?

When a hydrogen in an excited state transits back to the ground state, a photon (or series of photons) is emitted in accordance with the selection rules. When two free hydrogen atoms in the ground ...
0
votes
1answer
13 views

Detection of the He-nuclei in the historical Rutherford scattering experiment

Which method did Rutherford use to detect the Helium nuclei in his scattering experiment?
2
votes
3answers
175 views

Can a photon be absorbed by a proton?

When incident light passes through a hydrogen gas, for example, does it have 50% chance (since it's a 1:1 ratio of protons to electrons) of getting absorbed by the proton? Any chance at all? If no, ...
5
votes
3answers
105 views

Original papers on Hydrogen spectral lines

I am trying to find original experiments that had observed spectral lines from hydrogen or other gases. I am looking into experiments that motivated Niels Bohr to write his ideas on the hydrogen atom, ...
1
vote
1answer
74 views

Is it possible to isolate an individual atom?

I was reading about molecules and wondering about whether they could be individually isolated and "held" or "photographed" in some sense. Google showed that a rubidium atom was isolated, but it left ...
5
votes
1answer
308 views

Question on Pauli's Exclusion Principle

Pauli's EP says that electrons in a subshell will have opposing spins. Now, lets say I prepare two electrons with spin up. If I took an alpha particle ($\mathrm{He^{2+}}$) and added one of these ...
0
votes
1answer
92 views

How is magnetic field created in an atom according to quantum model

How is magnetic field created in an atom according to quantum model? I mean, we are taught about the magnetic field by bohr's model which assumes that electron revolves around the nucleus in a ...