Vibrational optical activity of chiral carbon nanoclusters treated by a generalized π-electron method.

摘要: Cross sections of inelastic light scattering accompanied by vibronic excitation in large conjugated carbon structures is assessed at the π-electron level. Intensities Raman and vibrational optical activity (VROA) spectra fullerenes are computed, relying on a single electron per atom. When considering only first neighbor terms Hamiltonian (a tight-binding (TB) type or Huckel-model), intensities captured remarkably well, based comparison with frequency-dependent linear response self-consistent field (SCF) method. Resorting to levels when computing spectral brings beneficial reduction computational cost as compared SCF. At difference total intensities, TB model found inadequate for giving left right circularly polarized components scattered light, especially molecular surface highly curved. To step beyond approximation, an effective Hamiltonian, including interaction all sites derived from all-electron Fockian, spirit Bloch-equation. Chiroptical cross-sections computed this novel method improve upon first-neighbor considerably, no increase cost. Computed VROA chiral fullerenes, such C76 C28, reported time, both conventional SCF models.