Abstract: | Using density functional theory, geometries and vibrational frequencies of linear chains NC2nN and HC2n+1N (n = 1~ 10) have been investigated.Time-dependent density functional theory (TD-DFT) has been used to calculate the vertical transition energies and oscillator strengths for the X 1∑+k → 11∑+u transition in NC2nN (n = 1 ~10) and X1∑+ → 11∑+ transition in HC2n+1N (n =1 ~7).On the basis of present calculations, the explicit expressions for the size dependence of the excitation energy and the first adiabatic ionization energy in both carbon chains have been suggested. |