Cryotrapping can also refer to a somewhat different effect, where molecules will increase their residence time on a cold surface without actually freezing (supercooling). There is a delay between the molecule impinging on the surface and rebounding from it. Kinetic energy will have been lost as the molecules slow down. For example, hydrogen does not condense at 8 kelvins, but it can be cryotrapped. This effectively traps molecules for an extended period and thereby removes them from the vacuum environment just like cryopumping.