Ab initio calculation of the molecular structure and electronic properties of carbodi-imide, HNCNH

Abstract

Results of ab initio SCF calculations on carbodi-imide (HNCNH) are reported. The geometry is optimized by the analytical-gradient method using the split-valence 4-31 G basis set. The most stable geometry exhibits the non-linear –NCN– frame with an NCN angle of 172.8°. The calculated rotational and inversion barriers of the N–H group are shown to be very low and are almost the same (3.84 and 3.54 kcal mol^–1 for rotation and inversion, respectively), confirming the configurational instability of this species. Some molecular properties have been calculated by the 6-31 G** basis set.