The terahertz time-domain and Raman spectra of corticosteroid hormones in the region of low-frequency infrared
vibrations have been measured. On the ground of quantum chemical calculations of the frequencies and normal modes
the assignments of vibrational bands in the THz-spectra are performed.
This report presents a theoretical investigation of the excited states and photo-physical properties of collsion complex
between molecular oxygen (dioxygen) and free-base porphin. A highly symmetric collision complex of the C2v point
group is calculated by multi-configuration self-consistent field method (MCSCF) method with linear and quadratic
response wavefunctions. Spin-orbit coupling (SOC) is not strongly affected by complexation. Spin forbidden character
of singlet oxygen emission is overcome by relatively strong SOC inside dioxygen, and the main effect of intermolecular
interaction is to enhance the Noxon band (b1Σ+
g - a1Δg) in the O2 molecule. MCSCF calculation of the collsion complex
explain very high efficiency of triplet-singlet energy transfer and photodynamic therapy sensibilized by porphyrins. We
have shown that porphin strongly perturbs many singlet-singlet and singlet-triplet transitions in dioxygen including
enhancement of Herzberg bands in ultra violet region. Vibrational activity in infra red absorption is also predicted in
agreement with some recent experimental data.