First principles study of the structure, electronic state, and stability of C m N 2 clusters

Geometric and electronic properties of C m N 2 ( m = 1–14) clusters have been investigated by density functional theory using the hybrid B3LYP functional and the 6‐311G( d ) basis set. Harmonic frequencies for these clusters are given to aid in the characterization of the ground states. These results show that C m N 2 ( m = 1–14) clusters form linear structures with D ∞ h symmetry. Two N atoms favor to bond at ends in linear isomers. The chains with odd m have triplet ground states whereas the ones with even m have singlet ground states. The calculated HOMO–LUMO gaps and ionization potentials all show that the C m N 2 ( m = 1–14) clusters with even m are more stable than those with odd m , which is consistent with the observed even–odd alternation of the time‐of‐flight signal intensities. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004