Distribution of Surface Recombination Energy of Spin-Polarized Hydrogen on Liquid Helium

By using bolometric detection of ESR we have observed that of order 1% of the two-body surface recombination energy of atomic hydrogen is deposited directly into liquid helium at the sample cell walls. Most of the energy is transferred from the recombination site by highly excited H2 molecules which are found to experience at least 150 wall collisions in order to release half of their rovibrational energy.