Helical molecular orbitals around straight-chain polyyne oligomers as models for molecular devices

摘要

Polyyne oligomers (H_2C_nH_2), with CH_2 group at each end of the oligomer, have been found to give helical molecular orbitals for the HOMO and LUMO and other molecular orbitals around the HOMO and LUMO when the two CH_2 groups are tilted from their equilibrium positions. This can be explained by the changes in the symmetry of H_2C_(2m+1)H_2 from D_(2d) to D_2, the former having degenerate molecular orbitals but the latter having non-degenerate orbitals. These helical molecular orbitals have been pointed out as being a kind of molecular device through which electrons pass.