QM dis

Key experimental observations: 

Key experimental observations Energy quantization Black-body radiation (Planck) E=hn Heat capacity of solid at low-T (Einstein) Spectra of atoms Wave-particle duality The photoelectron effect (Einstein) Electron diffraction (Davisson-Germer)

Slide2: 

Absorption/Emission Spectra of H atom Classical Theory Fails!

Slide3: 

Bohr’s model for H atom N. Bohr (1885-1962) Nobel prize 1922 n=1 n=2 n=3 n=4 Ef-Ei=hn

The photoelectric effect: 

The photoelectric effect Shining light onto metal can produce “photoelectrons” Vary the frequency and intensity of the light - observe the kinetic energy (velocity) of the photoelectrons Classical description of light (wave) predictions [using energy conservation] No dependence on the frequency of the light Higher kinetic energy with higher light intensity

Slide5: 

The photoelectric effect A. Einstein R. A. Millikan (1879-1955) (1868-1953) Nobel prize 1921, 1923

Slide6: 

Diffraction of electron beams C. J. Davisson (1881-1958) G. P. Thomson (1892-1975) Nobel prize 1937

Slide7: 

Particle-wave duality Prince Louis-Victor Pierrer Raymond de Broglie (1892-1987) Nobel prize 1929 R. P. Feynman (1918-1988) Nobel prize 1965 l=h/(mv)

Slide8: 

Wave and energy quantization However, mv is not arbitrary in QM, because l=h/(mv)  mv=h/l and l has to adopt a value such that the wave fits on the ring! l=2πr/n  mv=h/l =nh/2πr  E=n2h2/[(2π)2(2mr2)] n Z

Slide9: 

Wave and energy quantization However, mv is not arbitrary in QM, because l=h/(mv)  mv=h/l and l has to adopt a value such that the wave fits on the ring! l=2πr/n  mv=h/l =nh/2πr  E=n2h2/[(2π)2(2mr2)] n Z

Slide10: 

The Schrödinger’s Equation E. Schrödinger (1887-1961) W. K. Heisenberg (1901-1976) P. A. M. Dirac (1902-1984) Nobel prize, 1933 Nobel prize, 1932 HY=EY ^

Slide11: 

Born’s interpretation Max Born (1882-1970) Nobel prize, 1954 |Y(x)|2 x dx |Y(x)|2 dx Probability ~