About light interacting with matter

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Discussion Overview

The discussion revolves around the predictability of the color of solid objects based on their molecular formulas and the complexities involved in understanding how light interacts with matter. Participants explore the influence of molecular structure, neighboring molecules, and energy levels in both gases and solids.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that predicting the color of a solid object is possible if the absorption and re-transmission of photons by the molecule can be detailed.
  • Others highlight the complexity introduced by neighboring molecules affecting electron energy levels, suggesting that the situation is complicated and difficult to analyze.
  • A participant references Stephen Hawking's assertion that existing theories can make accurate predictions in most situations, implying that there may be a theoretical basis for predicting color based on molecular composition.
  • There is a discussion about how adding atoms changes the energy states, leading to a greater number of states and the formation of continuous bands of energy levels in solids.
  • Questions arise regarding the differences in emitted photon energies when molecules interact versus when they are isolated.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and agreement regarding the predictability of color based on molecular structure, with some acknowledging the complexity and lack of clarity in the interaction of light with solids. No consensus is reached on the feasibility of predictions or the adequacy of current models.

Contextual Notes

Participants note that the understanding of light-matter interaction in solids is less developed compared to gases, and that existing models may not fully capture the complexities involved. There is also mention of the distinction between solid state physics and quantum chemistry.

Who May Find This Useful

Individuals interested in the fields of physics, chemistry, material science, and those exploring the interaction of light with matter may find this discussion relevant.

snoopies622
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Is it possible to predict the color of a solid object based on its molecular formula?
 
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It is, if you can detail how the molecule/molecular formula will absorb/retransmit incoming photons.


Al
 
But what about the influence of neighboring molecules - don't they also affect the energy levels of a given electron? It seems so complicated. How does one even begin?
 
snoopies622 said:
But what about the influence of neighboring molecules - don't they also affect the energy levels of a given electron? It seems so complicated. How does one even begin?

Exactly. It is very difficult. As far as i know, our knowledge of said phenomenon at this point is more analytic than synthetic (i.e. our models, if present arent very good and an experiment would have to be conducted to see what actually happened).
 
Hmm.. I've always wondered about this question. Why is this red book red? this purple shirt purple? etc.

At the end of the first chapter of A Brief History of Time, Stephen Hawking says,

"...the partial theories that we already have are sufficient to make accurate predictions in all but the most extreme situations,"

so I've assumed that there's a way - at least in principle - to say, the formulae for the kind of molecules the make up this paint are so-and-so, therefore the paint is green. But I've never looked into the matter far enough to get anywhere. I know how it works with gases where the molecules are practically isolated from one another and the electron energy levels are discrete, but with solids I've never had a clear idea.
 
snoopies622 said:
I know how it works with gases where the molecules are practically isolated from one another and the electron energy levels are discrete, but with solids I've never had a clear idea.

Well, if you have an atom with two states, and add another atom with two states (and they interact), you end up with four states (you can view it as a combination of a1+b1, a1+b2, a2+b1, a2+b2). Add more atoms and you get even more states, eventually forming continuous bands of energy levels.

It's the same thing, just "smeared out" more. Although in practice they're different fields (solid state physics vs quantum chemistry, typically).
 
So when the pair jumps from state a1+b2 to a1+b1, the photon that's emitted is different from the one that would be released if the b molecule were alone and went from b2 to b1?
 
And state a1+b2 doesn't have the same energy as state a2+b1?
 
Hello? Should I have asked this question in the "Atomic, Solid State, Comp. Physics" section instead?
 

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