FIGURE 2. Isotropic magnetic field effects on C–P–F.

Transient absorption data recorded for frozen solutions of C–P–F showing the magnetic field-dependence of the recombination of the radical pair state, [ C ⁺–P–F ^-] . Apart from the upper part of a, all data are field-on minus field-off differences: A(B₀) - A(0). a, Top: absorption with and without an 8-mT applied field at 133 K. Bottom: difference signals as a function of temperature. All signals rise with the instrumental time constant (50 ns). b, Changes in the transient absorption of [ C ⁺–P–F ^-] at 119 K averaged over a 50-ns period centred at 100 ns and 400 ns after its formation. c, Changes in the transient absorption of [ C ⁺–P–F ^-] at 113 K caused by 39-T and 49-T applied magnetic fields. Error bars, 1 s.d.