LECTURE 22 Optical properties

LECTURE 22 Optical properties - SUMMARY FROM LAST CLASS...

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Dr. P. Lucas U of A MSE 110 Crystal properties: Graphite : layers of covalently bonded carbons with alternating double bond forming extended π system. Layers are stacked and held by weak Van der Waals forces. Properties: Brittle, high melting point, conducting, lubricant. Diamond : metastable form of carbon produced by high pressure. 3-D covalent network. Properties: extreme hardness, high thermal conductivity. Perovskite : ABO 3 a big metal atom A in the corners, a small metal atom B in the center, and oxygen atoms face centered. High temperature T>T c , cubic cell, transient dipole. Low temperature T<T c , tetragonal cell, permanent dipole. T>T c : polarizable material, high dielectric constant ε , used in capacitors. T<T c : permanent dipole, compression induce change in dipole length and charge of crystal surface. Reverse phenomenon applies. These materials are piezoelectrics . Used in positioning system, actuators, conversion of mechanical to electrical signal, sound detection/production. Zeolites : Open structures based on SiO 4 and AlO 4 tetrahedra connected by corners. Used for ion exchange, purification, heterogeneous catalysis. 100+ types of zeolites with specific pore size. SUMMARY FROM LAST CLASS
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Dr. P. Lucas U of A MSE 110 Light Light is an electromagnetic wave. An electric and magnetic field oscillating perpendicular to the direction of propagation. OPTICAL PROPERTIES OF MATERIALS In vacuum, the wave propagates at the speed of light c = 3×10 8 m/s . In air, the density of atoms is so low
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This note was uploaded on 10/06/2009 for the course MSE 110 taught by Professor Lucas during the Spring '08 term at University of Arizona- Tucson.

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LECTURE 22 Optical properties - SUMMARY FROM LAST CLASS...

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