Isothermal ramped fieldhyphen;desorption of water from metal surfaces

摘要

It is shown that water vapor deposited onto metal surfaces between 80 and 130 K can be isothermally desorbed by applying a ramped electric field. At a ramp rate of sim;1 MV/cm/s the desorption field strength for physisorbed layers of amorphous ice on tungsten and iridium surfaces is sim;80 MV/cm. As the ice layers desorb in the presence of the high electric field, positive ions are formed which are detected. During this process, the ice exhibits properties of an electrical conductor or a semiconductor.