Chemistry Reference
In-Depth Information
If we admit
jb
d
j > jb
s
j
, as reasonable and done by Lennard-Jones
(1937) in his original study, then we have a band gap
D ¼
2
ðb
d
b
s
Þ
,
which is of great importance in the properties of solids. Metals and
covalent solids, conductors and insulators, and semiconductors can
all be traced back to the model of the infinite polyene chain extended
to three dimensions (McWeeny, 1979).
