Tagged Questions
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0answers
19 views
Degeneracy of orbitals in magenetic field
Why is that in an external magnetic field(uniform) the degeneracy of d,f orbitals is lost but the degeneracy of p orbitals remain intact assuming the main cause of losing degeneracy is the difference ...
2
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1answer
62 views
Dark and bright areas around atoms in a scanning tunnelling microscope image
Recently IBM created world’s smallest ever animation on an atomic scale video. Researchers made the animation using a scanning tunnelling microscope to move thousands of carbon monoxide molecules to ...
0
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0answers
45 views
How large must the Quantum teleportation fidelity have to be in order for it to be useful?
This question relates and stems from my original question. Please read this one and the comments before answering this question.
Quantum Teleportation Fidelity
I know that for discrete variables ...
1
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0answers
79 views
why is the transition $3p^53d^2 \to 3p^63d^1$ (hydrogen atom) forbidden?
What I was thinking is that in 3d subshell (l=2) we have two electrons with $$m_l=-2$$ (spin up and down)
and if we move to 3p we will fill the last vacant position - that is $$m_l=1$$ with spin down ...
3
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4answers
250 views
How can the nucleus of an atom be in an excited state?
An example of the nucleus of an atom being in an excited state is the Hoyle State, which was a theory devised by the Astronomer Fred Hoyle to help describe the vast quantities of carbon-12 present in ...
1
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0answers
49 views
Where do electrons get the energy to remain in orbit? [duplicate]
As we know electrons continuously revolve around the nuclus without falling in it at a high velocity beating it's force of attraction. My question is where do electrons get energy to revolve around ...
2
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1answer
84 views
How is energy transferred between atoms in a collision?
Consider two bare protons. One (A) is stationary (relative to some arbitrary massless observer); the other (B) is approaching A at 1 m/s. When they collide, I assume that they bounce.
What is the ...
4
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3answers
141 views
Do electrons in multi-electron atoms really have definite angular momenta?
Since the mutual repulsion term between electrons orbiting the same nucleus does not commute with either electron's angular momentum operator (but only with their sum), I'd assume that the electrons ...
6
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2answers
145 views
Do the energy levels of electron orbitals change relativistically?
When an electron emits a photon from changing energy levels, the frequency of the photon depends on the difference between the energy levels.
But if someone is moving with respect to the atom, the ...
0
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1answer
178 views
Elastic collisions in Franck-Hertz experiment
Looking at a Franck-Hertz experimental setup, and given a potential difference such as $4.0\ V$ which is too small to excite out the first electron orbital, the electrons moving through the tube will ...
2
votes
1answer
101 views
What is the spatial mode of light or the spatial mode of a massive particle?
I'm extremely confused by what physicists mean by the spatial mode of light. I am also equally if not more confused by what the spatial mode of a massive particle is. Can anyone help me out by ...
2
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2answers
162 views
What's the difference between two Hydrogen atoms?
If we are given two Hydrogen atoms, would the only difference between them would be their quantum state (Energy level or eigen value, and the corresponding Orbital or eigen state) and their location ...
3
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2answers
245 views
Is it possible to recover the old Bohr-Sommerfeld model from the QM description of the atom by turning off some parameters?
Is it possible to recover the old Bohr-Sommerfeld model from the QM description of the atom by turning off some parameters?
Can we use Ehrenfest's theorem (or some other scheme) to reduce the QM ...
0
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1answer
94 views
What is changed when proton has finite radius?
How the field and interactions are changed when we assume that proton has finite radius in atom for example? What gives the finite size effect? Is it the higher moments of multipole expansion?
2
votes
2answers
298 views
Energy shift between hydrogen and deuterium
Stated: The atomic spectra of hydrogen and deuterium are similar however shifted in energies.
So im trying to explain why it is that the emission lines are shifted and how they are shifted.
Since ...
3
votes
4answers
974 views
Bohr's model of an atom doesn't seem to have overcome the drawback of Rutherford's model
We, as high school students have been taught that-because Bohr's model of an atom assigns specific orbits for electrons-that it is better than Rutherford's model. But what Rutherford failed to explain ...
3
votes
2answers
841 views
Bohr Model of the Hydrogen Atom - Energy Levels of the Hydrogen Atom
Why the allowed (stationary) orbits correspond to those for which the orbital angular momentum of the electron is an integer multiple of $\hbar=\frac {h}{2\pi}$?
$$L=n\hbar$$
Bohr Quantization rule of ...
4
votes
3answers
133 views
How do we know that internal conversion creates no intermediate photon?
I've read, from several sources, that in internal conversion -- an excited electron transferring its energy to another electron which is then emitted -- no intermediate gamma radiation is produced.
...
2
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4answers
657 views
How can one describe electron motion around hydrogen atom?
I remember from introductory Quantum Mechanics, that hydrogen atom is one of those systems that we can solve without too much ( embarrassing ) approximations.
After a number of postulates, QM ...
2
votes
1answer
242 views
Implementing simple atom model using density functional theory (DFT)
I am trying to write computer code which will find the energy and density function for a atom with Z protons and N electrons. I am working in 1D for simplicity and would like to make the overall code ...
2
votes
2answers
257 views
Why does optical pumping of Rubidium require presence of magnetic field?
The optical pumping experiment of Rubidium requires the presence of magnetic field, but I don't understand why.
The basic principle of pumping is that the selection rule forbids transition from ...
2
votes
2answers
252 views
At what angle does a single atom “reflect” a single photon?
Does this question make sense in the quantum world?
Imagining a single photon (wave packet?) interacting with a single atom (its electrons etc) how do we currently describe/define the emitted photon ...
3
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2answers
318 views
Is the electron wave function defined during photon emission
I have heard the term quantum leap to describe the (instantaneous?) transition from a higher energy orbital to a lower energy orbital. Yet, I understand that this transition time has now been ...
0
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0answers
310 views
Evaluating Transition probability between different states of Hydrogen atom
I am trying to evaluate the inner product $<2S_{\frac{1}{2}},F',F'_{3}|\delta^{3}(x)\sigma_{i}P_{i}|2P_{\frac{1}{2}},F,F_{3}>$ It's written in the form $<nl_{j},F,F_{3}|$ Where ...
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3answers
202 views
Is energy conserved in decay of hydrogen atom in superposed state?
This looks like a paradox.
Let's say we have an hydrogen atom. Superposition of states could be possible for electrons. But if an electron is in a superposition, I guess it could decay into a lower ...
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3answers
176 views
Atom Theory vs Quantum Physics
This never really occurred to me until now, so maybe it does not categorize a really important question, but according to Quantum theory anything that "is not observed is probability until it is ...
4
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3answers
342 views
Planetary model of atom still valid?
When I was in school, I learned (from Democritus) that an atom was
similar to a solar system, with the nucleus being the sun, and the
electrons being the planets. Of course, there are some ...
5
votes
2answers
791 views
Is the Mendeleev table explained in quantum mechanics?
Does anybody know if there exists a mathematical explanation of Mendeleev table in quantum mechanics? In some textbooks (for example in "F.A.Berezin, M.A.Shubin. The Schrödinger Equation") the authors ...
-1
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1answer
626 views
Radial Schrödinger equation
I found a problem that says:
Show by direct substitution that $R_{10}$ is a solution of Schrödinger's radial equation.
AFAIK Schrödinger's radial equation is
...
3
votes
1answer
283 views
What are independent parameters in Hellmann–Feynman theorem?
A typical example in textbooks about the application of Hellmann–Feynman theorem is calculating $\left\langle\frac{1}{r^2}\right\rangle$ in hydrogen-like atoms. Wikipedia has a nice demonstration of ...
10
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3answers
886 views
What really cause light/photons to appear slower in media?
I know that if we solve the maxwell equation, we will end up with the phase velocity of light is related to the permeablity and the permitivity of the material. But this is not what I'm interested in, ...
5
votes
1answer
482 views
Open shells in Quantum mechanics of multielectron atoms
This question: How do electron configuration microstates map to term symbols?
And the discussion of multielectron effects here: Quantum Computing and Animal Navigation
Inspired me to try to understand ...
1
vote
3answers
275 views
Is it possible to bind an entangled electron to the outer shell of an atom or just a proton?
Say we start with an entangled electron--positron pair and we separate them. I want to take the entangled electron and bind it to a proton or the outer shell of an atom.
Is it possible to do this ...
4
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3answers
1k views
Photon hitting an atom with higher energy than needed to ionize
Suppose we have an atom with several energy levels (e.g. an hydrogen), and it is hit by photons.
I know that in order to have the atom change energy levels, the photon must have an energy level ...
8
votes
2answers
7k views
What is in the space between a nucleus of an atom and its electrons?
There is a common analogy about the structure of an atom, such as the nucleus is a fly in the centre of a sports stadium and the electrons are tiny tiny gnats circling the stadium (tip of the hat to ...
3
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2answers
1k views
How does electron excitation relate to atomic orbitals?
Taking off from the Rutherford-Bohr model,
Figure 1. Rutherford-Bohr model.
when an electron absorbs energy (from light, heat, or otherwise) it jumps to a higher energy level, or shell. Then when ...
4
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2answers
2k views
Zero probability of finding an electron in the nucleus
One and the same electron in a p orbital and taking part in a common π (pi) bond has two lobes visualized as connecting through the nucleus. There is however zero probability of finding an electron at ...
5
votes
2answers
2k views
How does electron move around nucleus?
I need to get a nice picture about how electron moves around nucleus? I find concept of probability and orbitals quite difficult to understand?
1
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2answers
791 views
Appearance of atoms
I was watching a documentary entitled "The Atom" and one of the statements made was that Atoms behave differently when we look at them. I wasn't too sure about the reasoning behind this and i'm hoping ...
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7answers
2k views
Is mass quantized?
I learned today in class that photons and light are quantized. I also remember that electric charge is quantized as well. I was thinking about these implications, and I was wondering if mass was ...
