Phosphorescence parameters for platinum (II) organometallic chromophores: A study at the non-collinear four-component Kohn-Sham level of theory

► Explanation for the double exponential decay observed for Pt (II) organic chromophores. ► Corroborating evidence for exciton localization in the triplet state. ► Algorithmic development enabling relativistic four-component time-dependent DFT response theory calculations.