Relativistic effects in spectroscopy and photophysics of heavy-metal complexes illustrated by spin-orbit calculations of [Re(imidazole)(CO)3(phen)]+.
Abstract
Spin-orbit coupling (SOC) is an essential factor in photophysics of heavy transition metal complexes. By enabling efficient population of the lowest triplet state and its strong emission, it gives rise to a very interesting photophysical behavior and underlies photonic applications such as organic light emitting diodes (OLED) or luminescent imaging agents.
SOC affects excited-state characters, relaxation dynamics, radiative and nonradiative decay pathways, as well as lifetimes and reactivity. We present a new photophysical model based on mixed-spin states, illustrated by relativistic spin-orbit TDDFT and MS-CASPT2 calculations of [Re(imidazole)(CO)3(1,10-phenanthroline)]+.
An excited-state scheme is constructed from spin-orbit (SO) states characterized by their energies, double-group symmetries, parentages in terms of contributing spin-free singlets and triplets, and oscillator strengths of corresponding transitions from the ground state.