Matter Waves

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Matter Waves

• deBroglie Relation
• Davisson and L. H. Germer Experiment
• Two-slit Experiment

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Stuff
Exam 3 Monday, May 1
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Reading Question
Light consists of discrete, massless units called
1. quarks. 2. photons. 3. rotons. 4.
muons. 5. phonons.
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Reading Question
Light consists of discrete, massless units called
1. quarks. 2. photons. 3. rotons. 4.
muons. 5. phonons.
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Reading Question
The first evidence for matter waves was found in
the
1. de Broglie experiment. 2. Millikan
experiment. 3. Einstein-Bohr experiment. 4.
Davisson-Germer experiment.
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Reading Question
The first evidence for matter waves was found in
the
1. de Broglie experiment. 2. Millikan
experiment. 3. Einstein-Bohr experiment. 4.
Davisson-Germer experiment.
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Reading Question
Which particles were seen in this chapter to
undergo interference and diffraction?
1. Electrons. 2. Atoms. 3. Neutrons. 4. Both 1
and 2. 5. All of 1, 2, and 3.
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Reading Question
Which particles were seen in this chapter to
undergo interference and diffraction?
1. Electrons. 2. Atoms. 3. Neutrons. 4. Both 1
and 2. 5. All of 1, 2, and 3.
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Matter Waves

• Louis de Broglie proposed that electrons could
  have wave properties as well as particle
  properties. He found that the electrons
  wavelength was related to what classical
  property? Write the equation that relates these
  two properties.

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Matter Waves

• Below is the wave function (matter wave) for two
  particles. Which particle has the largest
  momentum? Explain.

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Matter Waves

• This wavelength is called the de Broglie
  wavelength. Calculate the de Broglie wavelength
  for an electron with a kinetic energy of 100
  eVs.
• How does this wavelength relate to the wavelength
  for visible light?
• What is the wavelength for a baseball (0.15 kg)
  thrown at 90 mph (45 m/s)?

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Matter Waves

• Bohr orbits

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Matter Waves

• C. J. Davisson and L. H. Germer Experiment 1928

Scattering electrons off polycrystalline Nickel.
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Matter Waves
Electron Scattering
electron diffraction pattern
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Matter Waves

• Electron Diffraction

Electrons
Light
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Class Question
A proton, an electron and an oxygen atom each
pass at the same speed through a 1-µm-wide slit.
Which will produce a wider diffraction pattern on
a detector behind the slit?
1. The proton. 2. The electron. 3. The oxygen
atom. 4. All three will be the same. 5. None of
them will produce a diffraction pattern.
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Class Question
A proton, an electron and an oxygen atom each
pass at the same speed through a 1-µm-wide slit.
Which will produce a wider diffraction pattern on
a detector behind the slit?
1. The proton. 2. The electron. 3. The oxygen
atom. 4. All three will be the same. 5. None of
them will produce a diffraction pattern.
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Mater Waves

• Electron Waves
• with a Scanning Tunneling Microscope

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Mater Waves
Electron Microscope
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Matter Waves

• Matter Waves

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Matter Waves

• Two-slit Experiment

Feynman said that if you understand the two slit
problem then you understand quantum mechanics
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Matter Waves
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Matter Waves
Electron In a Box
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Class Question
A proton, an electron and an oxygen atom are each
confined in a 1-nm-long box. Rank in order, from
largest to smallest, the minimum possible
energies of these particles.
1. EC gt EO gt EH 2. EO gt EC gt EH 3. EH gt EC gt
EO 4. EO gt EH gt EC 5. EH gt EO gt EC
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Class Question
A proton, an electron and an oxygen atom are each
confined in a 1-nm-long box. Rank in order, from
largest to smallest, the minimum possible
energies of these particles.
1. EC gt EO gt EH 2. EO gt EC gt EH 3. EH gt EC gt
EO 4. EO gt EH gt EC 5. EH gt EO gt EC
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Class Question
What is the quantum number of this particle
confined in a box?
1. n 3 2. n 4 3. n 5 4. n 6 5. n 8
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Class Question
What is the quantum number of this particle
confined in a box?
1. n 3 2. n 4 3. n 5 4. n 6 5. n 8
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Class Question
Cite one experiment that confirms the de Broglie
hypothesis.
1. Spectrum of blackbody radiation 2. X-ray
penetration depth 3. Electron diffraction 4.
Optical pumping 5. Nuclear magnetic resonance
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Class Question
Cite one experiment that confirms the de Broglie
hypothesis.
1. Spectrum of blackbody radiation 2. X-ray
penetration depth 3. Electron diffraction 4.
Optical pumping 5. Nuclear magnetic resonance