Figure 4.

Solvent-composition dependence for quantum yields of free-radical-ion formation in the system BP–anisole in ACN–H₂O mixture at pH 11 (black symbols). Quantum yield of ketyl radical BP formation in the system BP–anisole in ACN–H₂O mixtures at pH 3 (red symbols). The concentration of anisole was sufficiently high to quench the triplet almost totally (>90%). The solid line represents a fit of the experimental points to an exponential function A₀·exp(A₁·x_w), where A₀ = (3.8 ± 1.7) × 10^–6 and A₁ = 12.5 ± 0.5. The red vertical line marks where V_ACN ≈ V_w.