Condensation of Atomic and Molecular Hydrogen at Low Temperatures

Abstract

With the use of reflected modulated atomic‐beam techniques, the reflection of hydrogen atoms and molecules at cold surfaces has been examined. It was found that at low temperatures (∼4°K) hydrogen atoms reflect as atoms with a very high probability. The reflection of hydrogen molecules is strongly dependent upon the amount of water vapor condensed on the target previously to or simultaneously with the H₂. The fact that condensation of stable gases can be affected by simultaneous condensation of water vapor at temperatures exceeding the gases' normal boiling points leads to an application in the form of an extraordinarily inexpensive way to produce vacuums in the 10⁻⁵ mm Hg range.