Fig. 2. Excited state dynamics of TCPP ⁴⁻ and H ₂ TCPP ²⁺ . (a) Jablonski diagram for TCPP neutral environment (region I), showing the excitation into the singlet (green arrow), vibrational relaxation (black arrow), singlet relaxation (yellow arrow), intersystem crossing (grey arrow), and triplet relaxation (orange arrow) pathways. The same applies to H₂TCPP²⁺, i.e. fully protonated TCPP (region III), except that it does not have a split S₁ level (see text). (b) and (d) Transient absorption heatmaps on TCPP⁴⁻ and H₂TCPP²⁺ after excitation at respectively 515 nm and 665 nm. (c) and (e) Spectral slices of the heatmap at delay times 0.6 μs, 3.0 μs, 9.1 μs, 24 μs, 63 μs, 160 μs, 0.4 ms, 1.0 ms, 2.5 ms, and 6.4 ms from blue to red. The bleach positions correspond to the Soret bands in the steady state spectra (Fig. 1(b)). When fitting a single exponential to the bleach intensity time traces, lifetimes of 1.2 ms and 120 μs are obtained for TCPP⁴⁻ and H₂TCPP²⁺ respectively.