The preexponential factor in desorption — CO on Ni(111)

An XPS Study of the Interaction of Ultrathin Cu Films with Pd(111)

“…39 Therefore, Cu adopts the geometric lattice constant of the Pd(111) surface, yielding a Cu surface density that is very similar to that of Pd(111) (∼1.5 × 10 15 atoms cm -2 ). Furthermore, this surface density is approximately equal to the surface atomic density of Cu(100)(∼1.5 × 10 15 atoms cm -2 ), implying that the effective coordination (in plane) of Cu in the Pd(111) surface is likely very similar to that of a Cu(100) surface.…”

Laser-induced thermal desorption of CO on Ni(111): Determination of pre-exponential factor and heat of desorption

“…Conventional thermal desorption spectroscopy (TDS) is often used to deduce Ed and v. It has, however, been recognized that a separate determination of Ed and v with good accuracy requires a very careful execution of the experiment. Measurements of the number of tlesorbed molecules must be highly accurate and free of background noise [2][3][4][5][6]. Several methods have been developed to bypass the difficulties [7][8][9][10][11].…”

“…According to statistical theories [ 2,6] of molecular desorption, the pre-exponential factor b depends critically on the state the adsorbates are in. If the adsorbates are free to move around on the surface, v is roughly given by YM kgT/hm 1013/s.…”

Lattice-gas model of chemisorption on metal surfaces

“…14); таким образом, предэкспоненциальный фактор частично компен-сирует рост скорости десорбции при увеличении покрытия за счет уменьше-ния энергии активации десорбции. Данные для системы CO/Ni (111) оказа-лись противоречивыми: согласно 108 с ростом покрытия энергии активации десорбции уменьшаются, а предэкспоненциальный фактор примерно постоя-нен; в 113 получено, что с ростом покрытия предэкспоненциальный фактор возрастает примерно на 4 порядка, а энергия активации остается по-стоянной.…”