Solar wind implantation, H diffusion, and H₂ release pathway. Schematic illustration of the model pathway in which solar wind protons are implanted into the upper damaged rim of lunar regolith grains, become mobile H, occupy metastable O–H trapping sites, and are eventually lost through thermally controlled diffusion and recombinative H₂ release. The activation-energy distribution represents an effective description of the M³-sensitive retained H/OH reservoir rather than a unique mineralogical activation-energy spectrum.