MSE 460: Electronic Materials and Processing I

Problem set #6; assigned March 2

1. Ethylene has an optical absorption peak at 175 nm. Estimate the HOMO-LUMO separation for benzene.
2. For what length of p-conjugated chain will the HOMO-LUMO separation be < 1.4 eV. Use the Hückel theory solution I gave in lecture
   

   Ej = a+2bcos æ è jp N+1 ö ø

   (1)
3. Using the same equation as above, derive a simple expression for the HOMO-LUMO separation as a function of N in the limit of large N.

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On 02 Mar 2009, 14:52.