1
vote
1answer
21 views

How can we tell if a molecule is in thermodynamic equilibrium from scattering data?

We have a molecule that is emitting/absorbing photons. We know the Hamiltonian and that there are several levels. We count the emitted photons at different angles and frequencies. We can also do ...
0
votes
1answer
27 views

Correlation between Bohr-model and quantum physics

If you're looking at the probability of finding the electron of a hydrogen atom at a distance $r$ from the nucleus, it turns out that the Bohr model for the radius of the orbit only correlates with ...
2
votes
2answers
103 views

Why do electrons orbit protons? [duplicate]

I was wondering why electrons orbited protons rather than protons orbiting electrons. My first thought was that it was due to the small amount of gravitational attraction between them that would ...
1
vote
1answer
69 views

Rewriting the Hydrogen Schrodinger Equation as a system of differential equations

I have only ever seen the Schrodinger equation for the hydrogen atom written out in a form like this: $$ -\frac{\hbar^2}{2\mu}\left[\frac{1}{r^2}\frac{\partial}{\partial r}\left(r^2\frac{\partial ...
1
vote
1answer
43 views

Total magnetic moment in an atom

I have a doubt regarding the calculation of total angular momentum of electron in an atom.Which is the right way to do it? Method 1: Total magnetic moment $$ \begin{align} \vec{\mu_J} &= ...
4
votes
1answer
67 views

Where is quantum physics with regards to the periodic table?

In his Lecture's on Physics (circa 1960's) Richard Feynman wrote that so far physics has only been able to model (solve) the hydrogen and helium atoms. So now, more than 50 year's later where are we ...
0
votes
1answer
39 views

Question about one of the problems of the Bohr model

This is probably extremely basic physics that I don't know, but I'm still going to ask: Say in hydrogen, according to the Bohr model the electron is "really" orbiting the proton, and as a consequence ...
2
votes
2answers
71 views

What's the difference between hopping and tunneling?

My professor made a distinction between electron hopping (the closest wikipedia had an article on) and tunneling, saying that one (he didn't say which, but I assume hopping) was temperature dependent ...
15
votes
4answers
649 views

Why do electrons in an atom occupy only the stationary states?

When we talk about the elementary problems in quantum mechanics like particle in a box, we first calculate the energy eigen-function. Then we say that the most general state is the linear combination ...
8
votes
2answers
2k views

Why does electron move in an elliptical path?

According to Sommerfeld's atomic model, an electron moving around a central positively charged nucleus is influenced by the nuclear charge. As a result of which, the electron moves in an elliptical ...
0
votes
0answers
44 views

How to read this state in quantum physics?

I am having a little trouble understanding this state: $$ \,^3D\left[3/2\right]_{1/2} $$ What does the $[3/2]$ indicate here?
3
votes
1answer
147 views

Is there only radial motion in the Hydrogen ground state?

The ground state of the Hydrogen atom is spherically symmetric. In other words, the wave function Psi depends only on the distance r of the electron from the nucleus. As a consequence all ...
8
votes
2answers
502 views

Trouble understanding the Bohr model of the atom

In this article it says: The electrons can only orbit stably, without radiating, in certain orbits (called by Bohr the "stationary orbits") at a certain discrete set of distances from the nucleus. ...
2
votes
1answer
28 views

Reconciling electron subshell configurations and the Pauli exlcusion principle

I'd like to prefix this with an apology: I have no formal training in QP, and most of what I know has been obtained by reading Wikipedia. As such, it'd be really helpful if any answers took my lack of ...
1
vote
1answer
346 views

What is the difference between the Bohr model of the atom and Schrödinger's model?

What is the difference between the Bohr model of the atom and The solution of the Schrödinger equation for the hydrogen atom? Are there any difference between definition of the electric potential ...
1
vote
0answers
69 views

Why is graphene the only (stable) 2D sheet structure? [duplicate]

I know that Carbon molecules can form different structures depending on how they bond with each other: graphite, diamond, graphene and fullerene. As far as I understand, graphene is just a "sheet" of ...
0
votes
1answer
81 views

Is there any defect in Rutherford's atomic model according to quantum theory?

According to quantum mechanics charged bodies do not emit energy. Then why the atomic model of Rutherford has the defects of collapsing nucleus, continues spectrum.
8
votes
2answers
989 views

How does an electron move around in an orbital? Is it “wave-like” or random?

When an electron is moving around in it's orbital, is it actually moving around like a wave, like this video shows? (By wave-like, I mean, the "electron" in this video is showing it following a ...
1
vote
4answers
183 views

How does the electron jump across “gaps” in its orbital?

I saw on perhaps COSMOS, and have heard mention from other professors, that electrons sort of "teleport" or something, in their orbital and the quantum level. So looking at the orbitals for a lone ...
2
votes
1answer
43 views

Why is the full eigen function is product of eigen functions and not addition?

For example suppose there is a two electron system. Why is the full eigen function product of the spatial eigen function and spin wave function for the two electron system?
2
votes
1answer
119 views

Question about atom subshells

So my teacher told me that EACH shell contains 5 subshells (s, p, d, f, g) but what I don't understand is this The 1st shell has only 1 subshell (and not 5 like he said) and the number of ...
1
vote
1answer
46 views

Eigenfunctions for $1s$ hydrogen Schrodinger equation

I am a computer scientist and started my Phd in material science. The second course os my Phd is material simulation by computer. One the task is show the verification of the eigenfunction $1s$ from ...
1
vote
0answers
28 views

Stimulated emission and coherence

For a significant part of my life I have been taught that, if a photon of the "correct" energy meets an excited atom, the atom will then (with a certain probability) undergo transition to a lower ...
2
votes
4answers
231 views

Bond Angles - H2O vs CO2

H2O has a 109.5 degree bond angle, but CO2 has exactly 180 degrees. Is there a qualitative reason for this? It's hard to believe CO2 is exactly 180 degrees unless there were some symmetry, but the ...
2
votes
3answers
241 views

Why can't electrons fall into the nucleus?

I read a book on pop sci book on quantum mechanics and the author said that electrons do not fall into the nucleus due to quantum mechanics- which principles suggest this (I think it was Heisenberg's ...
1
vote
1answer
60 views

Formation of atoms question

Could you please, explain to me the logic of the folllowing process as you would do to your 8 y/o sister: Ubiquitousness and stability of atoms relies on their binding energy, which means that ...
1
vote
1answer
80 views

Total Angular Momentum of a Hydrogen Atom

Griffiths in his celebrated book named 'Introduction to Quantum Mechanics' discusses about the total angular momentum of a hydrogen atom on page 187. He writes: If a hydrogen atom is in the ...
0
votes
0answers
34 views

Uncertain if invoking uncertainty principle for wave function is handwaving [duplicate]

Why doesn't the electron collapse onto the proton in a hydrogen atom? One explanation seems to be given by the Heisenberg uncertainty principle, which follows from the purely physical assertion that ...
1
vote
1answer
74 views

Spectral series' formula of a given atom (other than hydrogen-like)?

The hydrogen spectral series is given by the Rydberg formula: The energy differences between levels in the Bohr model, and hence the wavelengths of emitted/absorbed photons, is given by the ...
1
vote
1answer
71 views

Wigner Threshold law in Photodetachment and Photoionization

I am writing this question here because I have a problem in understanding the Wigner Threshold law in Photodetachment and Photoionization. The Wigner Threshold Law is given by: $\sigma$=$E^{L+1/2}$. ...
1
vote
2answers
78 views

Stability of the hydrogen atom and positronium

I am trying to get a better understanding of why positronium decays while a hydrigen atom is stable. In the case of positronium, I can write an elementary process were the leptons annihilate into two ...
4
votes
2answers
290 views

Neil deGrasse Tyson says that electrons “teleport” between energy levels?

This page: https://blog.afach.de/?p=62 Discusses the error Neil deGrasse Tyson made when talking about electronic transitions (video included there). Tyson clearly said in his Cosmos series that ...
6
votes
2answers
1k views

Can I steal your electron?

The following paragraph has been extracted from the Wikipedia (Atomic orbitals): Simple pictures showing orbital shapes are intended to describe the angular forms of regions in space where the ...
2
votes
3answers
84 views

What does the $y$-axis represent in the atomic spectra and what is its significance?

The picture is an emission spectrum of Helium. The spectrum has sharp lines (peaks) at certain wave lengths characterizing it as helium. Agreed that it characterizes Helium as atomic spectral line ...
1
vote
0answers
27 views

What is it that makes an electron maintain a distance from the positively charged nucleus? [duplicate]

What is it that makes an electron maintain a distance from the positively charged nucleus? Why aren't electrons merely pulled into and absorbed by the nucleus ?
0
votes
1answer
58 views

Two-photon absorption and 3rd order susceptibility

I am referring to introduction of Section 12.5 Multiphoton Absorption and Multiphoton Ionization (Page no. 550 of Nonlinear Optics, Boyd-3rd edition) where it has been said that the two-photon ...
1
vote
1answer
58 views

Any simple reason why Helium in the ground state is diamagnetic?

I know the electrons are in the spin singlet state, and the spatial part of the wave function is an S-state. But that is not sufficient for it to be diamagnetic.
0
votes
0answers
32 views

Computing fine structure of terms in LS coupling,

In order to compute the fine structure of the terms in LS coupling (Russell-Saunders coupling), we must treat the hamiltonian $$H_2 = \sum_{\mbox{open subshells}} \xi(r_i) \vec{l_i}\cdot\vec{s_i}$$ ...
0
votes
0answers
15 views

Why photoelectron imaging is a 'complete' measurement?

In many articles and books, it says that photoelectron imaging gives a 'complete' information. What is mean by 'complete' measurement or a 'complete' information? Through photoelectron imaging ...
0
votes
3answers
109 views

Quantum mechanics scattering theory

When an electron absorbs energy and jumps to the another excited state by absorbing the photon and why it is always said that the electron will come back to $\hbar\omega/2$? Why doesn't the electron ...
1
vote
1answer
62 views

Coulomb potential in atoms other than hydrogen

The energy of an electron on $H$ atom is given by the formula: $-13.6 \; \text{eV}/n^2$. The constant value is born from $H$ dielectric constant and efective mass of the electron. My question is: ...
3
votes
0answers
79 views

What is a covalent bond?

What is a covalent bond, quantum mechanically? How does it hold the two atoms together, and at one point can you qualify the electron as being shated between two atoms, versus feeling attractive ...
1
vote
0answers
29 views

Covalent Bonds, Varities and Limits!

Related:http://chemistry.stackexchange.com/q/9459/ I was wondering, covalent bonds tend to share two electrons, apparently rarely more than three, and normally between two electrons. Can someone give ...
5
votes
1answer
230 views

Advanced atomic physics: From Liouville Equations to the Bloch equations

I'm trying to derive the Bloch equations from the Liouville equation. This should be possible according to this paper, where it discusses higher order Bloch equations (second order spherical tensors). ...
0
votes
0answers
14 views

Dipole and multipole bound state anions: Do these bound electrons behave exactly like conventional electrons in the molecular orbitals?

Recently, I read about dipole and multipole bound anions. Dipole bound anions are those, if I understood correctly, when an electron is attached electrostatically on a neutral molecule which is polar. ...
3
votes
3answers
179 views

Why are hydrogen energy levels degenerate in $\ell$ and $m$?

Is there a good physical picture of why the energy levels in a hydrogen atom are independent of the angular momentum quantum number $\ell$ and $m$?
0
votes
0answers
23 views

Coulomb splitting in atomic physics

In atomic physics, if a configuration with equivalent electrons in some shell (say Neodymium : $[Xe] 6s^24f^4$) gives same $L = \sum_i l_i$ and $S = \sum_i s_i$ ($i$ denoting individual spin and ...
0
votes
2answers
655 views

What is wrong with the Bohr model?

What is wrong about the Bohr model? Many books say it is wrong but doesn't say why and I don't know why.
-1
votes
1answer
44 views

Accleration and frequency

Recently, I was taught by my sir that the Acceleration of an electron of Bohr Atom is equal to its frequency. I am confused and didnt understand why it turns out to be equal
2
votes
1answer
104 views

On use of Hamiltonians for Helium

The Hamiltonian of helium can be expressed as the sum of two hydrogen Hamiltonians and that of the Coulomb interaction of two electrons. $$\hat H = \hat H_1 + \hat H_2 + \hat H_{1,2}.$$ The wave ...