02/07/2014PHY 712 Spring Lecture 101 PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 10: Complete reading of Chapter 4 A.Microscopic  macroscopic polarizability B.Clausius-Mossotti equation C.Electrostic energy in dielectric media

02/07/2014PHY 712 Spring Lecture 102

02/07/2014PHY 712 Spring Lecture 103 Focus on dipolar fields:

02/07/2014PHY 712 Spring Lecture 104 Microscopic origin of dipole moments  Polarizable isotropic atoms/molecules  Charge anisotropic molecules Polarizable isotropic atoms/molecules +q+q x E k=m   2

02/07/2014PHY 712 Spring Lecture 105 E +q+q xx k=m   2 Polarizable isotropic atoms/molecules – continued:

02/07/2014PHY 712 Spring Lecture 106 Alignment of molecules with permanent dipoles p 0 : + - E p0p0

02/07/2014PHY 712 Spring Lecture 107 Field due to collection of induced dipoles

02/07/2014PHY 712 Spring Lecture 108 Field due to collection of induced dipoles -- continued

02/07/2014PHY 712 Spring Lecture 109 Field due to collection of induced dipoles -- continued Claussius-Mossotti equation

02/07/2014PHY 712 Spring Lecture 1010 Example of the Clausius-Mossotti equation – Pentane (C 5 H 12 ) at various densities Density (g/cm3)Mol/m3e/e03V*(e/e0-1)/(e/e0+2) E E E E E E E E E E-28

02/07/2014PHY 712 Spring Lecture 1011 Re-examination of electrostatic energy in dielectric media

02/07/2014PHY 712 Spring Lecture 1012 Comment on the “Modern Theory of Polarization” Some references:  R. D.King-Smith and D. Vanderbilt, Phys. Rev. B 47, 1651 (1993)  R. Resta, Rev. Mod. Physics 66, 699 (1994)  R, Resta, J. Phys. Condens. Matter 23, (2010) Note: In general P is highly dependent on the boundary values; often it is more convenient/meaningful to calculate  P.

02/07/2014PHY 712 Spring Lecture 1013 Comment on the “Modern Theory of Polarization” -- continued