Excitation and ionization energies of substituted anilines calculated with density functional theory

Abstract

Valence electron singlet excitation energies (VEExE), valence electron ionization energies (VEIE), core electron binding energies (CEBE), and non-resonant Xray emission energies of substituted anilines and related molecules were calculated using density functional theory (DFT). The energy calculations were done with TZP basis set of Slater Type Orbitals. PW86x-PW91c, turned out to be the best XC functional among eight functionals tested for time dependent DFT (TDDFT) calculation of the singlet excitation energies of the substituted anilines. Using the XC functional, average absolute deviation (AAD) from experiment was 0.223 eV for eighteen cases with maximum absolute deviation of 0.932 eV. The valence electron ionization energies of the substituted benzenes were calculated by ΔSCF method with PW86x-PW91c. AAD from experiment was 0.21 eV. The CEBEs were calculated with the previously established method, named as scheme 2003. ΔCEBE(SMS),, sum of mono substituted (SMS) CEBE shift, and mutual interference effect (MIE) were defined and their values were calculated. Magnitude of MIE provides the degree of mutual interference between two substituents in a phenyl ring. Average absolute value of MIE was ca. 0.1 eV for the three isomers of phenetidine. Using the calculated valence electron ionization energies and the core electron binding energies of one of the phenetidines, some X-ray emission energies were calculated.