1. Bohr Model of the Hydrogen Atom
Neils Bohr (1885 – 1962)

2. Matter Waves
Louis de Broglie (1892 – 1987)
l = h/p

3. Electron Diffraction Observed in 1927
Crystalline Nickel as an Electron Target
L. H. Germer
C. J. Davisson
…studying electron scattering from a nickel target at Bell Laboratories. After heating
the target to remove an oxide coating that had accumulated during an accidental
break in the vacuum system, they found that the scattered-electron intensity as a
function of the scattering angle showed maxima and minima. Their target had
crystallized, and by accident they had observed electron diffraction.
Physics by Paul A. Tipler

4. Electron as “Orbiting” Wave
Constructive Interference
Destructive Interference
(Standing Wave)

5. Quantized “Orbits” Due To Standing Wave Req.

6. Reformulations of Classical Mechanics
Isaac Newton
(1643 – 1727)
Joseph Louis Lagrange
William Hamilton
(1736 – 1813)
(1805 – 1865)

7. Now What? The wave function contains all possible
information about a system, so instead of
speaking of “the state described by the
wave function Y,” we simply say “the
state Y.”
Quantum Chemistry by Ira N. Levine
Erwin Schrodinger (1887 – 1961)

8. What is the Wave Function?
Quantum mechanics does not say that an electron is
distributed over a large region of space as a wave is
distributed. Rather, it is the probability patterns
(wave functions) used to describe the electron’s
motion that behave like waves and satisfy a wave
equation.
Quantum Chemistry by Ira N. Levine
Max Born (1882 – 1970)