A nucleus made of protons and neutrons surrounded by a cloud of electrons equal in number to the protons.
-4
votes
0answers
49 views
Why does an object with higher velocity gain more mass? [closed]
if we inject pure energy into a object capable of moving will it affect the structure of its atoms creating bigger neutrons, electrons and protons making the object increase its size affecting its ...
0
votes
0answers
18 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 ...
1
vote
1answer
53 views
Energy required for ionizing Helium
The energy required to remove both electrons from the helium atom in its ground state is 79.0 eV. How much energy is required to ionize helium (i.e., to remove one electron)?
...
1
vote
2answers
51 views
How does one subtract two light beams?
From what I understand, it seems like you can only "add" beams together. You can use a beam combiner, basically using a beam splitter in reverse, to combine two beams. In homodyne detection, you use a ...
2
votes
1answer
59 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
votes
1answer
52 views
Difference between atom and elementary particle questioned
Hydrogen ion doesn't have one electron which clearly mean that it has only one proton..So hydrogen ion is only a proton. Am I right, please make it clear. If hydrogen ion and proton are same that how ...
0
votes
1answer
82 views
Atoms in our body
Our body of course exchanges some atoms with environment every day however are there some of atoms which stay with us a life time?
2
votes
1answer
64 views
How fast did hydrogen atoms travel when they were first formed in the early universe?
I can't seem to find any data on this, is it a known value?
1
vote
0answers
16 views
Electron Configuration and Binding [closed]
Boron with an electron configuration of $1s^22s^22p^1$ has an atomic weight of $10.811u$. What is the total binding energy for 11Bs if $Mn = 1.008665u$ and $Mp = 1.007825u$.
I cannot find anything ...
4
votes
2answers
135 views
Graphene +1 extra carbon bond
I'm not a physicist just a curious mind, so please go easy!
I was just watching a BBC Horizon Documentary that featured a piece on the recently discovered material Graphene. One of the facts ...
1
vote
1answer
30 views
Minimum atomic clearance permitting motion
Suppose you were to build the piston and cylinder in a car engine atom-by-atom. Let's just say carbon, since you can make a lot of different shapes due to it's high valence.
So assuming you make the ...
0
votes
1answer
64 views
What is longitudinal relaxation time and transverse relaxation time？
How do we define the longitudinal relaxation time and transverse relaxation time?
0
votes
1answer
103 views
How electrons act under rotating magnetic field?
I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
0
votes
0answers
44 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 ...
8
votes
1answer
343 views
Why is carbon dating limit only 40,000 years?
For an example, when they tried to get the carbon dating for presence of Aboriginal people in Australia they get to the number 40,000. But it could be much earlier. Why is that 40,000 years limit for ...
0
votes
2answers
126 views
Why is electron presented in books, pictures as a sphere?
Why is electron presented in books, pictures as a sphere, when in fact it's not?
1
vote
2answers
220 views
The number of degrees of freedom of a monatomic gas
Suppose that I have a monatomic gas sample consisting of $N$ atoms (e.g., $N$ argon atoms); thus there are no vibrations or rotations. How many degrees of freedom does the system have?
Does the ...
1
vote
0answers
78 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 ...
32
votes
3answers
1k views
Can the solar system really fit in a thimble?
Almost every time somebody talks about atoms, at some point they mention something like this:
If we remove the spaces between the atoms and atomic components, we can fit the solar system in a ...
3
votes
4answers
232 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
vote
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 ...
1
vote
2answers
81 views
Quantum yield and spontaneous decay
I'm trying to figure out how many atoms are decaying spontaneously in a span of 2 seconds. Let's say that the quantum yield is 0.45, and that the lifetime "τ" (tau) is 10 microseconds.
Then I found ...
0
votes
0answers
50 views
Where to find probability density plots for all elements?
Does anyone know where I can find something similar to this, but for all elements?
I would love to find something with the same image quality.
Also, is there any software that can produce images ...
2
votes
1answer
83 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 ...
2
votes
1answer
84 views
Why do some liquid metals have anomalously-high surface tension/heat of vaporization ratios?
In a didactic article, Victor Weisskopf estimated the size of molecules in a liquid from measurements of their surface tension and heat of vaporization. If atoms are exceedingly small, then only a ...
0
votes
2answers
128 views
Does hidden variable quantum mechanics imply the collapse of atoms(electrons falling into the nucleus)?
why do atoms not collapse on themselves. Doesnt this problem rule hidden variables as invalid as the heisenburg uncertainty is the solution to the problem because it says electrons exist in a ...
4
votes
3answers
138 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
votes
2answers
144 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 ...
2
votes
2answers
427 views
What exists in the Space between atoms
Apologies to all if this has been asked before, I searched but was unable to find one similar.
This is a question that has been bugging me for a while that i haven't really been able to find a ...
1
vote
0answers
28 views
What methods exist for us to measure the position and momentum of atoms that make up molecules?
In reference to this paper, http://iopscience.iop.org/1355-5111/8/1/014, we are able to localize atoms using homodyne measurement. Would it be too naive to consider we can measure the position of ...
2
votes
1answer
78 views
Is the spin state of an atom related to the polarization of the photon it spontaneously emits?
From literature I've been reading, I find that scientists are able to "map" atomic states onto photon states. Are they talking about spin states and corresponding photon polarization states? Can ...
0
votes
1answer
171 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 ...
1
vote
3answers
190 views
What does a subatomic charge actually mean?
I was recently reading a popular science book called The Canon - The Beautiful Basics of Science by Natalie Angier, and it talks about subatomic particles like protons, neutrons and electrons in ...
2
votes
1answer
133 views
Explanation on Atomic Orbitals and Molecular Orbitals
We were reading about atomic structures and bond making and my teacher told me that when two atoms are fused or when they make bond, There are two orbitals formed. 1-Bonding Molecular Orbital & 2- ...
2
votes
1answer
97 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
votes
2answers
160 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 ...
0
votes
1answer
209 views
Why isn't Hydrogen's electron pulled into the nucleus? [duplicate]
Possible Duplicate:
Why do electrons occupy the space around nuclei, and not collide with them?
Why don’t electrons crash into the nuclei they “orbit”?
From what I learned in chemistry, ...
3
votes
2answers
242 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 ...
7
votes
2answers
278 views
why dosen't a charged particle radiate energy in circular motion in a uniform magnetic field?
I have studied in my Physics course that one of the drawbacks of Rutherford's atomic model was that when an electron will revolve around the nucleus, it is undergoing acceleration and so it should ...
2
votes
4answers
163 views
Computer Science Modeling of Physical World
I am curious what efforts have been made to date to define virtual computer worlds based on the physics we know in the real world?
I think it would be awesome to say start off with an atom defining ...
1
vote
1answer
42 views
Rotation of diatomic homonuclear molecule
I know that the rotation energy of a diatomic homonuclear molecule is $E_{Rot}=\frac{\hbar J(J+1)}{R^2 M}$. Does the axis of rotation depend on $J$? With respect to which axis does the molecule for ...
2
votes
3answers
162 views
can I move the atom core only?
I was wondering if it is possible to move the atom core and leave behind the electrons. I can imagine that the electrons will follow the core. But what if the speed of the core is almost the same as ...
3
votes
2answers
120 views
Why is there a factor of 1/2 in the interaction energy of an induced dipole with the field that induces it?
In this paper, there's the following sentence:
...and the factor 1/2 takes into account that the dipole moment is an induced, not a permanent one.
Without any further explanation. I looked ...
0
votes
1answer
93 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?
1
vote
1answer
171 views
Do atoms expand with universe? [duplicate]
Possible Duplicate:
Why space expansion affects matter?
Why does space expansion not expand matter?
As we know, the universe is expanding, galaxies are away from each other. But what ...
2
votes
0answers
100 views
Is the translational information all that matters, or do we need to take into account internal states?
For anyone in this community that's familiar with quantum teleportation, I need desperate help. I am currently working on my senior thesis and my goal is to teleport a molecule.
Background:
So in ...
4
votes
4answers
231 views
Spontaneous radiation
The usual explanation of spontaneous radiation is that the energy eigenstates are perturbed by QED interaction, so that the eigenstates obtained from single-particle QM are no longer eigenstates of ...
2
votes
2answers
293 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 ...
0
votes
0answers
69 views
Wondering about what would happen if all the atoms in the univerise scatter into proton and neutron? [closed]
What if the all the atom in the universe scatter into proton and neutron?In another word, would the all the matter in the universe disappear?
Inspire by the answer of one of my question: A question ...
3
votes
4answers
958 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 ...
