Structural and electronic properties of novel nanoscale C4nS4n molecules

We have designed novel ring molecules, C4S4n, which contain only carbon and sulfur atoms and performed Density Functional Theory (DFT) calculations on C4nS4n for n = 4,6,8. We have also done Hartree-Fock (HF) calculations on C24S24 and compared HF and DFT results for C24S24. DFT calculations showed that the minimum energy (optimized) geometries of neutral C4nS4n molecules have D-nh symmetry for n = 4,6,8. However, for (C24S24)(Q) molecules with Q = +1, +2, DFT geometry optimizations lead to the structures with the point group symmetry to C-2, C-2v and D-2h for (C24S24)(+), (C24S24)(2+) (singlet state) and (C24S24)(2+) (triplet state), respectively. Large structural differences between HF and DFT results for (C24S24)(+) indicate the importance of electron correlation effects for these molecules. It is also found that the triplet state of (C24S24)(2+) has lower energy. (C) 2003 Elsevier B.V. All rights reserved.