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H Atom 21 cm Line

Explore the secrets of the Milky Way galaxy through quantum physics and historical discoveries. Discover the hidden depths of the Galactic Centre and unravel the mysteries behind nuclear and electron spins. Dive into classical models of nucleons and magnetic fields, and learn about Fermi contact terms. Delve into electron densities, electric fields, and magnetic field regions shaping cosmic structures. Uncover the enigma behind the 21 cm radio spectrum and Doppler Shift phenomena. Join us on a cosmic journey through science and history.

johnjlewis
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H Atom 21 cm Line

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  1. H Atom 21 cm Line

  2. Is the Milky Way a Spiral Galaxy like this one?

  3. Because of the scattering by gas and dust in the disk

  4. Because of the scattering by gas and dust in the disk S  1-4

  5. Because of the scattering by gas and dust in the disk S  1-4 We can only see (in the visible) about 1/6 (ca 6000ly) of the way to the Galactic Centre

  6. View towards the Galactic Centre

  7. Nuclear and electron spins paired

  8. Nuclear and electron spins paired

  9. Nuclear and electron spins paired Nuclear and electron spins parallel

  10. Nuclear and electron spins paired Nuclear and electron spins parallel F = I+S = 0 F = I+S = 1

  11. Fermi and Hargreaves Contact Term Nuclear and electron spins paired Nuclear and electron spins parallel F = I+S = 0 F = I+S = 1

  12. Classical picture of the nucleus as a spinning charge shell which gives rise to two magnetic field regions B= Bint + Bext

  13. Classical picture of the nucleus as a spinning charge shell which gives rise to two magnetic field regions B= Bint + Bext

  14. Classical picture of the nucleus as a spinning charge shell which gives rise to two magnetic field regions B= Bint + Bext Bint internal uniform magnetic field

  15. Classical picture of the nucleus as a spinning charge shell which gives rise to two magnetic field regions B= Bint + Bext Bint internal uniform magnetic field Bext external magnetic field dipolar

  16. Electron density s electron r

  17. Electron density s electron p electron r

  18. Electron density s electron p electron r H = Bnucleus .electron

  19. r H =  Bnucleus(r).e(r) d

  20. s electron density r H =  Bnucleus(r).e(r) d

  21. s electron density External dipolar term r H =  Bnucleus(r).e(r) d

  22. s electron density dipolar term r H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext)

  23. s electron density dipolar term r H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d + Bext (r).e(r)d

  24. s electron density dipolar term r H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d + Bext (r).e(r)d

  25. s electron density dipolar term r H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d

  26. s electron density dipolar term r Bnucleus  I H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d

  27. s electron density dipolar term r Bnucleus  I e  S H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d

  28. s electron density dipolar term r Bnucleus  I e  S H = a I . S H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d

  29. s electron density dipolar term r Bnucleus  I e  S H = a I . S Fermi contact term H =  Bnucleus(r).e(r) d Bnucleus= (Bint + Bext) H =  Bint (r).e(r) d

  30. a = (8/3h) geBgH N(0)2

  31. a = (8/3h) geBgH N(0)2 ge electron g factor

  32. a = (8/3h) geBgH N(0)2 ge electron g factor B Bohr magneton

  33. a = (8/3h) geBgH N(0)2 ge electron g factor B Bohr magneton gH proton g factor

  34. a = (8/3h) geBgH N(0)2 ge electron g factor B Bohr magneton gH proton g factor N nuclear magneton

  35. a = (8/3h) geBgH N(0)2 ge electron g factor B Bohr magneton gH proton g factor N nuclear magneton (0)2 absolute value of the electron density at the nucleus squared

  36.  1s = (ao3)-1/2 exp (-r/a0)

  37.  1s = (ao3)-1/2 exp (-r/a0)  1s(0)2 = 1/ ao3

  38.  1s = (ao3)-1/2 exp (-r/a0)  1s(0)2 = 1/ ao3 a = 1420.4057 MHz

  39.  1s = (ao3)-1/2 exp (-r/a0)  1s(0)2 = 1/ ao3 a = 1420.4057 MHz ca 21 cm

  40. Historical Summary Fermi and Hargreaves calculated a in 1930

  41. Historical Summary Fermi and Hargreaves calculated a in 1930 Rabi measured in lab 1949

  42. Historical Summary Fermi and Hargreaves calculated a in 1930 Rabi measured in lab 1949 Van der Hulst suggested that this line might be detectable from space about 1945

  43. Historical Summary Fermi and Hargreaves calculated a in 1930 Rabi measured in lab 1949 Van der Hulst suggested that this line might be detectable from space about 1945 Ewan and Purcell detected radio spectrum in 1951 Harry Kroto 2004

  44.  -v Blue shifted +v Red shifted  Doppler Shift / = / = v/c Harry Kroto 2004

  45. Harry Kroto 2004

  46. Harry Kroto 2004

  47. Harry Kroto 2004

  48. Harry Kroto 2004

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