2. Rick Smalley

3. Magnetic Pulsed Valve

6. Hole for the laser pulse

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

8. Nozzle Plasma Skimmer hole Mass Spectrometer

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

10. Skimmer action more slowly

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

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

13. Harry Kroto 2004 H−C≡C−C≡C−C≡NH−C≡C−C≡C−C≡N H−C≡C−C≡NH−C≡C−C≡N H−C≡C−C≡C−C≡C−C≡NH−C≡C−C≡C−C≡C−C≡N

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

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

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

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

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

20. H−C≡C−C≡C−C≡C−C≡NH−C≡C−C≡C−C≡C−C≡N

23. Circumstellar Molecule Abundances Agúndez et al Carbon Chains in TMC1 HC 5 N HC 7 N HC 9 N HC 3 N

24. 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 C 11 + C 15 + C 19 + and C 23 + Should be strong

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

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

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

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

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

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

31. Try to simulate the conditions in the laboratory

32. Graphite

33. Perhaps changing the disk to graphite and adding say NH 3 to the buffer gas would produce HC 7 N etc Graphite

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

35. Silicon Carbide had produced SiC 2 which had been detected in stellar spectra SiC