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Rick Smalley

Rick Smalley. Magnetic Pulsed Valve. Magnetic Pulsed Valve. Magnetic Pulsed Valve. Hole for the laser pulse. Laser. Laser pulse creates a 10,000 o carbon plasma. Helium. Graphite. Skimmer hole. Nozzle. Mass Spectrometer. Plasma.

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Rick Smalley

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  1. Rick Smalley

  2. Magnetic Pulsed Valve

  3. Magnetic Pulsed Valve

  4. Magnetic Pulsed Valve

  5. Hole for the laser pulse

  6. Laser Laser pulse creates a 10,000o carbon plasma Helium Graphite

  7. Skimmer hole Nozzle Mass Spectrometer Plasma

  8. Supersonic Expansion into the vacuum chamber cools the clusters to very low temperatures The very sharp edged skimmer skims the expanding pulse into a very narrow beam

  9. Skimmer action more slowly

  10. Rick Smalley at Rice University in Texas had developed a laser vapourisation technique to make metal clusters Aluminium

  11. I suggested that if we replace the metal by graphite …as the carbon atoms react I expected them to form linear carbon chains ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

  12. H−C≡C−C≡N H−C≡C−C≡C−C≡N H−C≡C−C≡C−C≡C−C≡N Harry Kroto 2004

  13. ..and so simulate the conditions which produced the carbon chain molecules in the carbon rich Red Giant Star IRC 10216

  14. Laser Laser pulse creates a 10,000o carbon plasma Helium Graphite

  15. The plasma pulses fly across the vacuum chamber …add the signals from many plasma pulses – say 100

  16. TOF-MS Time of Flight Mass Spectrometer Pulsed UV Laser

  17. Hintenberger Franzen and Schuy Z Nat 1963 Mass spectrum of arc discharged graphite

  18. H−C≡C−C≡C−C≡C−C≡N

  19. Carbon Chains in TMC1 HC3N HC5N HC7N HC9N Circumstellar Molecule Abundances Agúndez et al

  20. The Huckel 4n+2 rule predicts carbon rings with 6 10 14 18 22 electrons should show “aromatic” character ie In the positive ion mass spectrum C11+ C15+ C19+ and C23+ Should be strong

  21. Strong 11 15 19 23 Weak 13 17 21 25

  22. Idea was to create a carbon plasma blown out of a carbon star

  23. Laser Replace the silicon disk by graphite (carbon) Helium Silicon disk Carbon disk

  24. Laser Laser pulse creates a 10,000o atomic plasma Helium Silicon disk

  25. Laser Laser vapourisation supersonic nozzle developed by Rick Smalley Helium Silicon disk

  26. …and produce the molecules we had detected by radioastronomy

  27. Try to simulate the conditions in the laboratory

  28. Graphite

  29. Perhaps changing the disk to graphite and adding say NH3to the buffer gas would produce HC7N etc Graphite

  30. Plasma in lab Exploding Star Try to reproduce the stellar plasma in the laboratory

  31. Silicon Carbide had produced SiC2 which had been detected in stellar spectra SiC

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