What is the true nature of an atom and how can we visualize it?

[jochemspek]

Hi,

I am a graphics programmer / animator and would like to play around
and try to visualize an atom. I think I can do better than the run of the mill
spheres or blobs as they are normally portrayed. I have a decent physics
background, I know QED by Richard Feynman by heart, and I have some
math background. I understand that the wavelength of visible light is too
large in order to resolve an atom, but what would theoretically happen
to a high frequency photon when it is scattered by a hydrogen atom ?
Say the photon has a wavelength < 0.01 nanometer. How would you go about
calculating the path of a photon coming from behind an H atom, and onto
your retina ?

Thanks for any insights.

best regards,

Jochem van der Spek

 

[zincshow]

A 0.01nm photon would have 124KeV mass, considering the electron in the hydrogen atom is about 500KeV and the proton is about 940MeV, almost all the interaction will be with the electron. Compton scattering talks about this kind of interaction, bumps around the electron but not the heavier proton and would look pretty neat in a nice animation. You actually only need 13.6eV to ionize the hydrogen atom (knock the hydrogen electron away from the proton).

 

[Bill_K]

You don't need to guess what they look like - here is an actual image of some atoms. This is for real - not just an artistic portrayal. I'm sure you can find more.

 

[RonL]

You don't need to guess what they look like - here is an actual image of some atoms. This is for real - not just an artistic portrayal. I'm sure you can find more.

The same as an image of gold atoms. As I recall from some time ago ? the statement that seeing a live image, would produce the appearance of an agitated high frequency vibration at each atom. Can that be confirmed ?
This image is what makes it hard for me to release the Bohr model of an atom. The effort to understand some things about magnetic fields related to particles has put me in a nightmare of study and research that keeps expanding in an overwhelming volume of related things.

Study without guidance is a terrible way to find answers progress has been a little obvious by how some posts are easier to comprehend than they were a year or more in the past. THANKS to PF

 

[jochemspek]

Bill_K, I am aware of RTM images (I once saw a movie of a layer of gold atoms moving about in a lecture, but I can't recall either the lecture, nor can I find the footage online. If anyone has a link that'd be great) but what I am after is an interactive rendering of what the atom would look like if it were between your eye and a high frequency lightsource. And if your eye would be as small as the atom.

zincshow, Thanks for the link to Compton scattering, very helpful ! Am I right if I understand that it talks about the electron as a point ? does the size of an electron matter (or could it be made to matter) so that in the rendering you could zoom in onto the electron ?

Another question is the position of the electron. Am I right in supposing that I would have to calculate the probability of finding an electron at a certain position around the nucleus, calculate the compton scattering for that location and then blend in the result of that calculation by a factor related to the probability ?

Thanks,

J

 

[zincshow]

Electrons would be considered very tiny, certainly smaller than the Lorentz radius of 3 femtometers (0.0003 nm), but also think about the speed of motion of things. Electrons are in the attosecond (1 as = 10-18 s) regime. In contrast, atomic motion occurs on the femtosecond (1 fs = 10-15 s) timescale and have been mapped in solids in real time using femtosecond X-ray sources. The heavy nucleus vibrates around but mostly in response to the heat of the sample. For a solid, the nucleus vibrates around a specific location on a grid. For a liquid, the nucleus vibrates and flows around relative to the location of other nucleus.

Attosecond spectroscopy is starting to pin down the location of electrons that are moving 1000's of times faster than the nucleus of the atom due to their lighter weight. Many electrons are going to cluster around the nucleus of the atoms, others will contribute to the bonding between atoms. Other electrons are floating free. Often they are described as forming grids and seas in the sample, within and around the atoms. I think the speed of light is 0.3 nanometers per attosecond for some reference.

 

[jochemspek]

allright, I won't be bothering with that, then : ) For now, I think I know what to do. Thanks a bunch !

 

[cmcraes]

If i could quickly add my own opinion here i would say it would look like a microscopic particle of whatever element it was. However just a 'generic atom' I think would be most accuratly portraid by a cloud of electrons surrounding the nucleus in a shperical shape looking somewhat like the 'white fuzz' of a tv (but maybe a different colour) and the nucleus being a mess of quarks flying around and gluons going everywhere.
But i would animate that as if the nucleus was was much slower, and it would look like a clump of quarks (and a pair of Each three quarks in a translucent sphere)each sphere containing a blue, a red and a green quark. slowly moving around and occasionally swaping gluons with each other, swaping colors at the same time. i hope that made sence!

 

[jochemspek]

hi cmcraes, thanks for your ideas ! however, the point of my exercise would be to avoid any 'artificial colouring' like colouring the quarks. I would like to portray a single atom the way we would see it if our eyes could see the sub-nanometer frequency domain. So I'll go with calculating the electron orbitals and then calculating the compton scattering from one or more photonsources.

 

[cmcraes]

Okay i see what you mean, i wasnt sure at first if you meant like a good visul representation or a more realistic aha anyway Id love to see the finished product one day

 

[sophiecentaur]

hi cmcraes, thanks for your ideas ! however, the point of my exercise would be to avoid any 'artificial colouring' like colouring the quarks. I would like to portray a single atom the way we would see it if our eyes could see the sub-nanometer frequency domain. So I'll go with calculating the electron orbitals and then calculating the compton scattering from one or more photonsources.

There's more to it than that, though. Your photons of sub-nanometre wavelength would have such high energy that they would disturb / destroy the very thing you would want to be looking at. There is no valid description of things in those terms, once you get that small; any artistic interpretation would be no more than just that and could even promote a false idea - particularly if it were made really pretty and appealing.

 

[zincshow]

You may get some inspiration from pictures like these from X-Ray photonics: X-rays inspire electron movies at: http://www.nature.com/nphoton/journal/v6/n10/full/nphoton.2012.247.html

You need a subscription for the article, but the pictures are free.

 

[7555]

Hi,

I am a graphics programmer / animator and would like to play around
and try to visualize an atom. I think I can do better than the run of the mill
spheres or blobs as they are normally portrayed. I have a decent physics
background, I know QED by Richard Feynman by heart, and I have some
math background. I understand that the wavelength of visible light is too
large in order to resolve an atom, but what would theoretically happen
to a high frequency photon when it is scattered by a hydrogen atom ?
Say the photon has a wavelength < 0.01 nanometer. How would you go about
calculating the path of a photon coming from behind an H atom, and onto
your retina ?

Thanks for any insights.

best regards,

Jochem van der Spek

Atom in the imagination...
Dark spheres with particles floating in its surface...

 

[dipole]

An atom really is a little blob though. From the outside it's a cloud of negative charge centered on the nuclear. The electron has no distinct orbit or trajectory or location even.

 

[zincshow]

... The electron has no distinct orbit or trajectory or location even.

What is Attosecond spectroscopy seeing if the electron has no trajectory or location? What are atomic orbitals if there are no electrons in them?

 

[dipole]

I don't know much about attosecond spectroscopy, but I didn't say the orbital contains no electron. It certainly does, but the idea that an electron has some well defined position in space is just not true, at least within the framework of Quantum Mechanics, which is the correct description of nature as far as anyone can tell.

Really, the electron is everywhere not nowhere (well actually there are some places it is definitely not, such as at the origin for any orbital with $l \neq 0$). It's just mostly in some vicinity of the nucleus, on the scale of what is called the Bohr radius. The wave function is completely deterministic, but all the wavefunction can tell you about the electron is the probability amplitude of finding it at a certain position at a certain time, and nothing more because really there is nothing more to be said.

This is why path integrals exist, because the electron can be anywhere (almost) and do anything (almost), and you have to sum all of the infinite possibilities when you consider how the electron is behaving.

 

[zincshow]

... the electron is everywhere not nowhere (well actually there are some places it is definitely not, such as at the origin for any orbital with $l \neq 0$). It's just mostly in some vicinity of the nucleus, on the scale of what is called the Bohr radius. The wave function is completely deterministic, but all the wavefunction can tell you about the electron is the probability amplitude of finding it at a certain position at a certain time...

I would agree, the Bohr radius is about 53 picometers (0.5 angstroms) and the location of the electron is a function of the timescale you measure it at. Attosecond spectroscopy can pin down measurements at that kind of accuracy.

 

[chill_factor]

You can't image a hydrogen atom with a high energy photon. It may ionize the atom. Low energy imaging techniques do not rely on photon scattering.

 

[sophiecentaur]

My problem with this whole thread is the title. The term "look like" implies optical wavelengths and a very mechanistic picture of an atom. Surely the whole of Physics for the last hundred years has acknowledged that all we can ever do is to produce a map of the structure and how that structure affects the way it will interact. A graph of probability density of the electrons around the nucleus is just a graph, despite being very useful. False colour may enhance what the graph tells us but it still doesn't tell us what the atom actually 'look like'.

 

[physwizard]

i don't think anybody can ever see the atom. that's why its called atomic hypothesis, and not atomic fact! quantum theory works, but does it make sense?

 

[milesyoung]

quantum theory works, but does it make sense?

How do you determine if something "makes sense"?

Quantum physics might have many counterintuitive aspects, but it seems rather arrogant to think that nature should somehow abide by human intuition.

 

[sophiecentaur]

How do you determine if something "makes sense"?

Quantum physics might have many counterintuitive aspects, but it seems rather arrogant to think that nature should somehow abide by human intuition.

Agreed. In order to learn one thing you may have to forget everything.

There's no instant gratification in Physics.