A theoretical study of the structure and conductivity of polycytosineacetylene

Inspired by the helical structure as well as the conductivity of DNA and substituted polyphenylacetylenes, a new kind of substituted polyacetylene is introduced. More specifically, polycytosineacetylene ((RC CH) n , R = cytosine) with a trans-polyacetylene backbone is investigated theoretically. The neutral and cationic geometries are optimized as single helical chains with n = 20. It is found that when an electron is removed the polymer stretches from 19.80 A to 28.41 A. The polyacetylene backbone in the optimized cationic polymer exhibits the formation of a soliton. It is predicted that a doped polycytosineacetylene would have good conductivity, and would also behave as a nanomechanical spring and as a piezoelectric material.