Ab initio NMR chemical shifts in hard carbon nitride compounds

Abstract

We show that NMR chemical shift spectroscopy could help to identify the crystalline phases of hard carbon nitride compounds. To this purpose we compute the NMR chemical shifts of defect zinc-blende,cubic, alpha, beta, and graphitic C3N4 with with a newly developed ab initio method. The C shifts can be used to identify the CN bonds and to characterize C hybridization. The N shifts distinguish the alpha C3N4 from the beta C3N4 phases, and indicate the presence of the graphitic phase.