Chemical structure vs excitation frequency (photons)

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Discussion Overview

The discussion revolves around predicting the frequency of photons released when a molecule, such as benzene, is excited and then relaxes. It explores the relationship between chemical structure and excitation frequency, including the potential for lasing and the properties of meta-materials.

Discussion Character

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

Main Points Raised

  • One participant inquires about resources for predicting photon frequencies released by excited molecules, specifically mentioning benzene.
  • Another participant suggests consulting the NIST Chemistry WebBook for spectral data on benzene, including IR and UV/Vis spectra.
  • A question is raised regarding the relationship between the frequency a substance emits and its potential to lase, with some uncertainty about the conditions required for lasing.
  • There is mention of meta-materials that can absorb one frequency and emit another, prompting a discussion about the existence of such materials and their properties.
  • One participant expresses curiosity about the size of the meta-stable region for these materials and what frequencies they can accept to emit a desired frequency.
  • A participant shares their academic background, indicating they are taking a course in solid state electronic devices and plan to study quantum mechanics, suggesting a desire to deepen their understanding of the topic.

Areas of Agreement / Disagreement

Participants express varying degrees of uncertainty regarding the conditions under which materials can lase and the properties of meta-materials. No consensus is reached on the specifics of these topics.

Contextual Notes

Participants do not clarify the assumptions behind their statements regarding lasing conditions and the properties of meta-materials, leaving some aspects of the discussion unresolved.

Who May Find This Useful

Individuals interested in the relationship between molecular structure and photon emission, as well as those studying solid state physics and quantum mechanics, may find this discussion relevant.

rppearso
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Is there a text, or set of texts, on how to predict what frequency of photon is released when a particular molecule is brought to an excited state and then relaxes?

So for example if you were to put, say, benzene into an electrical tube and excite it what frequency would be released and more importantly why?
 
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DrClaude said:
The best is to look at spectra. A good source is the NIST Chemistry WebBook.

For instance, on the page for benzene, you will find IR and UV/Vis spectra: https://webbook.nist.gov/cgi/cbook.cgi?Name=benzene&Units=SI

So if a substance/material gives off a certain frequency does that mean that it could also lase? Is there a book of meta-materials, such as materials that can accept one frequency to put electrons into an excited state but give off a different photon when the electrons drop back down?
 
Last edited:
rppearso said:
So if a substance/material gives off a certain frequency does that mean that it could also lase?
Not necessarily. Many substances can be made to lase, but you not necessarily at any frequency where transitions can occur.

rppearso said:
Is there a book of meta-materials, such as materials that can accept one frequency to put electrons into an excited state but give off a different photon when the electrons drop back down?
It is not clear for me what you are after. Maybe if you look up chemical dye lasers you will find something.
 
DrClaude said:
Not necessarily. Many substances can be made to lase, but you not necessarily at any frequency where transitions can occur.It is not clear for me what you are after. Maybe if you look up chemical dye lasers you will find something.



About mid way through it states there are materials where you can put in one energy and get out another energy. Thus it seems to me with such a material you could in effect pump this material with an easy to attain energy/frequency and get back a more difficult to attain frequency energy?

But the big question is how big is that meta stable region (what frequencies/energies will it accept) in order to give off the desired frequency?

I am currently taking a course in solid state electronic devices and plan to take a course in quantum mechanics next semester to help me figure this stuff out.
 

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