Our dynamics methodology is based on full dimensional trajectory surface hopping (TSH) in conjunction with a linear vibronic coupling (LVC) model. We follow a hybrid approach, recently developed by one of us, based on the combination of time-dependent density functional theory (TD-DFT) PESs and multiconfigutational second order perturbation theory (CASPT2) SOCs. Further methodological details are described below, in Supplementary Note 1, and ref. 30.