SCF ab-initio ground state potential energy surfaces for HCN and HCN^-

SCF computations for the ground state potential surfaces of HCN and HCN- are performed. These calculations predict that the ground state geometry of the radical anion is Re(CH) = 2.12 bohr, Re(CN) = 2.33 bohr and the bond angle θ = 121.7°. The calculations also show that the CH bond in HCN- is much weaker than in HCN and is similar to the CH bond in HCO. The computed electron affinity is -1.95 eV. Since the minimum on the potential energy curve for the anion is above the neutral curve rapid auto-ionization should occur to HCN and an electron. © 1978.