Study of charge transfer transition in benzene–ICl complex in gas phase and in CCl4 medium by ab initio and TDDFT methods

Applying the time dependent ab initio and DFT methods under the PCM formalism, the ground and excited state geometries of the benzene–ICl complex have been optimized at the HF, B3LYP and MPW1PW91 levels in gas phase and in CCL4 medium. The I atom of ICl is oriented towards the benzene ring; the I–Cl bond is above a C–C bond being slightly inclined (≈7°) to the C6-axis of benzene. Complexation increases the I–Cl bond length. The CT absorbtion band, located by calculating the ground-to-excited state transition electric dipole moments of the complex, agree well with reported experimental value.