ABSTRACT
The localized-density-matrix (LDM) method [Yokojima and Chen, Chem. Phys. Lett. 292, 379 (1998)l is employed to simulate the optical responses of very large carbon nanotubes. The PPP and PM3 Hamiltonians are used to describe the electrons in the systems, and the time-dependent Hartree-Fock (TDHF) approximation is employed to calculate the linear optical responses. Real space reduced density matrices for different oscillators are examined, and thus the nature of dipole activated excitations is understood.
