Title: MNDO Studies on Electron Affinity and Ionization Potentials of Polycyano Derivatives of some Unsaturated Hydrocarbons and Benzene
Abstract: Semiempirical MNDO calculations with optimization of geometry were carried out for several polycyano derivatives of some unsaturated hydrocarbons and benzene. The results show that the MNDO method overestimates the AEA s (adiabatic electron affinity) by about 0.575 eV. as is seen from the equation AEA exp = 0.998 AEA MNDO - 0.575; R = 0.9995. It was found that there exists a linear correlation between the energies of LUMO and the AEA's of the investigated compounds: AEA = - 1078 LUMO + 0.387; R = 0.9979 for 40 points. MNDO does not show a linear correlation of AEA with IP (ionization potential). Generally, with increasing number of cyano substituents in unsaturated hydrocarbons the energy of HOMO and LUMO decreases, but this may not necessarily be true for higher molecular orbitals.