Figure 6.

Resonance Raman kinetic measurement of X-ray-induced photoreduction in a myoglobin crystal. The difference spectrum between the unexposed spectrum (blue) and a spectrum after exposure to 1.5 MGy (red) shows reduction of the heme in the X-ray beam as a peak shift from 1371 cm⁻¹ to 1359 cm⁻¹. Owing to the high sensitivity of the instrument, the reaction could also be followed in real time, showing the dose-dependence of the reduction (inset). Power at the sample was 15 mW and acquisition time for each spectrum was 10 s.