A coupled electron-lattice model of a saturated homopolymer, such as a poly(organosilylene), is introduced. It shows that the states available in the polymer for the addition or excitation of electrons, or holes, are localized intragap states that are spontaneously generated by bond-order polaron formation.

• Received 6 October 1986

DOI:https://doi.org/10.1103/PhysRevLett.58.937