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Electron Microscopes

Electron Microscopes. 27-7. Developed in the 1950s Two Dimensional Image Electrons are accelerated by a Voltage of 10 5 V These Electrons have a wavelength of about .004nm Practical resolution is .1 to .5nm This is still 10 3 better than visible light 400-800nm.

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Electron Microscopes

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  1. Electron Microscopes 27-7

  2. Developed in the 1950s • Two Dimensional Image • Electrons are accelerated by a Voltage of 105V • These Electrons have a wavelength of about .004nm • Practical resolution is .1 to .5nm • This is still 103 better than visible light • 400-800nm Transmission Electron Microscope

  3. Electron Microscope

  4. Electron Microscope

  5. Resolutions to 1nm • Produce 3D image • 1st commercial product 1965 Scanning Electron Microscope

  6. Scanning Electron Microscope

  7. Scanning Electron Microscope

  8. Scanning Electron Microscope

  9. Developed in the 1980s • .1nm resolution laterally • .01nm resolution vertically • Uses Quantum Tunneling 30-12 Scanning Tunneling EM

  10. Scanning - Tunneling

  11. Scanning - Tunneling

  12. Atomic Spectra 27-11

  13. Atomic Spectra

  14. Bohr Model relates the jump down between excited states of the atom to the energy of a photon • Each line of the spectrum is a photon step • The larger the step, the more energy the photon • Therefore the shorter the wavelength • And higher frequency Bohr Model

  15. Emission Spectrum

  16. Absorbtion Spectrum

  17. Rydberg Constant • R = 1.0974 x 107m-1 • Balmer Series • Lyman Series • Paschen Series Hydrogen Series

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