[en] The effects of residual coupling interactions on the newly discovered decay ²²²Ra→ ¹⁴C+ ²⁰⁸Pb are investigated. The couplings to the low-lying collective excitations of ²⁰⁸Pb produce an order of magnitude enhancement in the tunneling probability. A new possible mechanism for this decay is discussed whereby a ¹²C fragment is transformed into ¹⁴C by picking up two neutrons as it tunnels out