All 42331 time steps accumulated in the stationary regime of the dynamics in the high-energy window (Table ) were used to compute the nuclear ensemble fluorescence spectrum with Eq. ( ) using J = 0.05 eV for all states. The fluorescence lifetime [Eq. (2)] is reported in Table together with the experimental results from Ref. 9. NEA predicts a fluorescence lifetime of 55 ns for the high-energy window, which is in excellent agreement with the experimental result, 62 ns. For the low-energy window, the theoretical prediction, 89 ns, is 2.3 times shorter than the experimental measurement. The most likely reason for this difference is that while the experimental results are for excitation at the S2 band origin, our simulations consider excitations at 4.0  0.1 eV, 0.45 eV above the computed S2 band origin (see Table ). This larger energy excess causes transition energies, oscillator strengths, and S2 populations to be bigger than those at the band origin, yielding shorter fluorescence lifetimes.