The area under the phosphorescence spectrum in terms of rad does not represent quantum yield but a lifetime. Employing Eq. ( ), we obtain rad = 2.97  0.03 ms, shorter than the vertical value computed at the T1 minimum, 4.6 ms. The NEA phosphorescence lifetime, however, is in outstanding agreement with the experimental results, between 2 and 4.3 ms, depending on the setup . The only other theoretical estimate of the phosphorescence lifetime is by Ou and Subotnik , 1.81 ms. Their calculation is equivalent to our vertical lifetime [Eq. ( )] with the 3 n*→S0 transition calculated at TDDFT with the B97X functional. All these values are summarized in Table . k0: 9-eV e --impact, 3.12-eV emission 600 1.7 k0: 9-eV e --impact, 3.32-eV emission 1300 0.8 Many experimental results are available for benzaldehyde (see Table ), which may lead to misunderstandings regarding which values we should take for comparison with theory. Two types of reaction rates are reported the phosphorescence rate (kP) and decay rate (k0). The relation between them is 00