according to the Rayman paper, Rayman uses short and long wave radiation.
What spectrum of wavelengths does this concern? Because I examine the influence of different light intensities on plants I may have to use a different factor for convert W/m2 in µmol/m² depending on the wavelengts used in Rayman.
RayMan uses the typical meteorological definitions for short and longwave radiation. This means, that shortwave radiation is anything in between 300nm and 3.000nm, while longwave radiation is 3.000nm to 50.000nm. As RayMan only deals with energy fluxes, this is not resolved to any spectrum. However, maybe you could apply the average solar radiation spectrum at sea level as an approximation (considering if there is direct radiation or not)?