Importantly, C is spin-allowed in catalytic cycle of methane-to-methanol reaction (i.e., the resting state and all intermediates have the same ground-state spin) (Supporting Information Tables and). of methane-to-methanol conversion, we calculate kinetics properties associated with oxo formation and HAT with NEB and potential energy scans, respectively (see Computational Details). The radical rebound step has been shown to be nearly barrierless and not involved in the turnover-determining transition state (TDTS) in our previous work , and so we do not attempt to compute a barrier for it.