raginrayguns:

raginrayguns:

ok but weird question are any of you like structural engineers that understand vibration and damping really well? It turns out this is super important in organic pigments and fluorophores, they’re these kind of stiff kind of floppy things that start jiggling once they absorb light…

I tend to think within the “classical nuclei, quantum electron” picture at absolute zero.

So there’s an organic molecule with the ground state electron wavefunction, and nuclei are point particles with 0 momentum, positioned to minimize ground state energy. Then it absorbs light, and now it’s in an excited state. But the geometry isn’t the minimum energy geometry for the excited state, so now there’s feynman-hellman forces on the nuclei. So they move to the geometry that minimizes the excited state, but when they get there, they have momentum. And now the molecule is vibrating, the nuclei oscillate around the minimum-energy geometry. And eventually it emits light, and there’s some randomness in the emission frequency depending on where it is in that oscillation when it happens. So we get some spectral broadening, and some energy lost as heat

(via sun-lit-goth)

  1. raginrayguns said: @tallitalianguy and yes those are all organic pigments. Organic molecules that act as pigments
  2. raginrayguns said: @tallitalianguy yeah i think there’s a stokes shift in raman spectroscopy too but it’s also there in fluorescence
  3. schneakyverene reblogged this from manyblinkinglights
  4. tallitalianguy said: Further, what do you mean by organic pigments? Phtalocyanines and alizarine? Quinacridone? Pigments, dyes and colourants in general are so complicated tbh
  5. raginrayguns said: @manyblinkinglights yeah exactly
  6. manyblinkinglights reblogged this from intactics
  7. tallitalianguy said: Anyway, not a background in eingeenering but in art conservation
  8. tallitalianguy said: Sorry, it’s 2:30 am for me and I am still a bit confused.. isn’t stokes more of a raman emission thing? I am sure that after a bit of sleep I’ll manage to understand it a smidge better
  9. raginrayguns said: @tallitalianguy yes this is fluorescence and the geometry change im describing is responsible for the stokes shift (at the new geometry excited state energy is lower, but ground state energy is higher, so the difference is smaller, so the emission energy is lower than absorption energy)
  10. tallitalianguy reblogged this from sun-lit-goth
  11. sun-lit-goth reblogged this from intactics
  12. intactics reblogged this from transgenderer
  13. hirosensei reblogged this from transgenderer
  14. scarecrowomen reblogged this from transgenderer
  15. raginrayguns posted this
    ok but weird question are any of you like structural engineers that understand vibration and damping really well? It...