From: luweitest@address.invalid   
      
   On 2017-7-6 20:28, ggherold@gmail.com wrote:   
   > ...   
   > I'm not sure about metals.  But for semiconductors* we use to do reflecatnce   
   > spectroscopy and see all the exciton states between the bands.  They   
   > looked like the derivative of an absorption.... And now I mumble something   
   > about the Kramers-Kroneig relation, which is all I remember of the theory.   
   >   
   Talking about semiconductors, I also have a confusion why Si has no k   
   (imaginary part) peak at about about 1100nm (corresponding to band gap   
   1.1ev, where there should be an absorption peak ).   
      
   --   
   Regards,   
   Lu Wei   
   PGP key ID: 0x A12F EF75 92CC E1EA   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)