THERMAL FIELD DESORPTION SPECTROSCOPY OF CHEMISORBED HYDROGEN FOR A SINGLE-STEP SITE

The steady state molecular hydrogen ion yield from a single atomic step site of a [110]-oriented tungsten and of a [100]-oriented rhodium crystal is determined as a function of surface temperature using mass and energy resolved probe hole field ion microscopy. A second order kinetic model is developed to fit the experimental data thus obtaining the hydrogen binding energy. For local fields of about 3 V/angstrom the data are close to values obtained from thermal desorption spectroscopy. A comparison is made with calculations of the field-adsorption binding energy of atomic hydrogen on a jellium surface based on density functional theory,