The excited states of a porphine–quinone complex under an external electrostatic field calculated by TDDFT

The potential energy curves (PECs) of the Q, B, and the lowest charge transfer (CT) states of a porphine–2,5-dimethyl-1,4-benzoquinone (PQ) complex have been studied by using the time-dependent density functional theory (TDDFT) with the CAM-B3LYP functional without and with the presence of an external electrostatic field. The PECs calculated using CAM-B3LYP with the original parameters α = 0.19, β = 0.65, and μ = 0.33 a 0 - 1 are practically identical with those obtained using BH&HLYP. Applying of CAM-B3LYP with parameters α = 0.19, β = 0.81, and μ = 0.25 a 0 - 1 yields PECs of the excited states that agree well with the PECs calculated previously using the CC2 method.