Figure 3.

Schematic illustration of the temporal information contained within a scattered x-ray pulse when τ₀ = 0 and α = 90°. Different photons within the x-ray pulse scatter from the crystal at different time delays following (or preceding) reaction initiation. As such, the intensities recorded at x′₁ and x′₂ (given by integration over the dashed vertical lines) consist of scattering contributions from several temporally distinct species. Taking the difference between I(x′₂) and I(x′₁) in the limit as x′₂ → x′₁, we observe that gradients in the recorded intensities are proportional to the difference between the native crystal scattering intensity and the scattering intensity of the species present at τ = ΔT − x/c, Eq. 5.