Surface-enhanced nuclear spin conversion in 13CH3F

The nuclear spin conversion of a molecule is the modification of the total nuclear spin I of its equivalent atoms. This phenomenon is observed by measuring the relaxation rate of a gas sample initially prepared with a population of spin isomers far from the equilibrium given by nuclear spin statistics. New experimental data obtained at low pressure show a surface-induced enhancement of the nuclear spin conversion in 13CH3F. Contrary to binary collisions in the gas phase, hitting the surface induces direct conversion. Several mechanisms are proposed.