With respect to Eq. ( ), the rate k can also be separated into FC-, HTVC-and SVCrelated components. In our quantitative calculations of S-T crossing rates of 7-PhQAD, we only keep the first two terms of Eq. ( ) and ignore the last two second-order spin-vibronic interactions. However, the contribution of SVC to the rates is roughly evaluated in Section 4.4 and Section S3 in the supporting information (SI).