Effect of atomic disorder or chain length on the stability of photoinduced polarization inversion.

The effect of atomic disorder or chain length on the stability of photoinduced polarization inversion has been studied. The atomic disorder was simulated by square-random or Gaussian-random model. It was found that for the square-random distribution case, photoinduced polarization inversion remains steadily when atomic disorder is less than [FRACTION SHAPE="CASE"][NUM]1[/NUM][DEN]8[/DEN][/FRACTION]a (a is the lattice constant of polyacetylene), the reversion polarization disappears and gets into normal polarized state when the disorder is stronger than over [FRACTION SHAPE="CASE"][NUM]1[/NUM][DEN]8[/DEN][/FRACTION]a. The reason of a normal polarization resulted from the strong lattice disorder was discussed. The relationship between the reverse polarization of biexciton state and the confinement constant t[sub e] as well as the variation of chain length was also studied. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]