Geometries and electronic properties of carbon-nitrogen clusters C8N4 and C8N4±

The geometry optimization and frequency analysis for the low-lying electronic states of C8N4 and its ions are performed at the DFT/6-31G(d) level. Their energies are calibrated at the CCSD(T)/6-31G(d) level of theory. Ionization energy, electron affinity, binding energy of C8N4, and anion photoelectron spectra of C8N4− are provided at the CCSD(T)/6-31G(d) level. Mulliken populations, leading configurations, bond orders, and compositions of molecular orbitals are used to examine the bonding characteristics in the low-lying electronic states of C8N4 and its ions. It is surprising to find that the ground state of C8N4 is the open shell 5A1 state. Interestingly for the low-lying electronic states of C8N4 and its ions, their structures significantly corrugated, which may be caused by their larger [N]/([N] + [C]) ratios. In addition, the similarities and differences between C8N4 and C10N2(II) are analyzed and discussed.