Dependence of Young’s modulus oftrans-polyacetylene upon charge transfer

Abstract
The effect of charge transfer (CT) on the Young’s modulus of trans-polyacetylene was studied with a molecular-orbital cluster model incorporating a charged soliton and with an infinite-chain model using band theory. The results of both models agree with one another very well. The Young’s modulus (Y) of trans-polyacetylene changes up to 7% with CT of up to 0.25e per CH unit. The calculated changes of the geometry upon CT agree with experiments. The asymmetry of the variation of structure and Y with respect to the sign of the CT is due to second-neighbor antibonding interactions in both the soliton and and models.