(a) Time-dependent integrated intensity of the CO diffraction peak, which was fitted with two exponential functions. Red and blue curves are the fitted fast (2 ps) and slow dynamics (57 ps), respectively. The black curve is the corresponding best fit to the data. (b) Time-dependent reflectivity change ΔR/R at a wavelength of 800 nm. The time traces were fitted with a fast (red curve, 0.5 ps) and slow (blue curve, 2.7 ps) exponential recovery in addition to a constant background (grey curve), representing a long-living meta-stable state in the local charge channel. The black curve is the corresponding best fit to the data. (c) Fast and slow recovery timescales deduced from the integrated intensity of CO (τCO) and optical ΔR/R data (τΔR/R). No difference can be discerned between the dynamics measured at 30 K and 50 K. The red-, green- and blue-shaded areas are guides-to-the-eye for the three dynamics deduced from both CO diffraction peak and ΔR/R data. Temporal resolution was taken into account as a Gaussian convolution in the fitting processes. The error bars are determined by 95% confidence interval of the fit.