Geometries and electronic structures of metastable C2N4 and its ions.

We carried out the computational studies on the geometric and electronic properties of electronic states of metastable C(2)N(4) (m-C(2)N(4)) and corresponding ions using the CASSCF and DFT(B3LYP)/CCSD(T) techniques. The optimized geometries of electronic states, vibrational frequencies, Mulliken populations, bond orders, and average polarizabilities are computed at the DFT level while the relative energies of the electronic states, ionization energy, electron affinity, binding energy of m-C(2)N(4) are calculated at the CCSD(T) level. The anion photoelectron spectra of m-C(2)N(4)(-) are also predicted. It is interesting to find that the relative energies of the electronic states of m-C(2)N(4) cluster linearly correlate with the amount of charge transfer between N and C atoms and that, however, there is no charge transfer between C and N atoms upon electron ionization or electron attachment.