Model B reproduces a situation of spontaneous emission due to the strong coupling between the system, initially in the vibrational ground state of the electronic excited state S 1 , and the cavity, that is resonance with the S 1 -to-S 0 transition at the minimum of the S 1 PES. We use the Hamiltonians of Eqs. ( ) and (27), with parameters: k = 0.020 E h m e /h 2 , a = 3.0 a -2 0 , b = 0.01 E h , ∆ = 0.17 E h , R 1 = 2.0 a 0 , R 2 = 2.0 a 0 , R 3 = 3.875 a 0 . The coupling between the system and the cavity is encoded in ω = 0.17 E h and in g = 0.01 (ea 0 ) -1 .