AVS 53rd International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM2
Calcium Adsorption on MgO(100): Calorimetric and Structural Studies

Thursday, November 16, 2006, 8:20 am, Room 2002

Session: Reactivity of Oxide Surfaces I
Presenter: C.T. Campbell, University of Washington
Authors: C.T. Campbell, University of Washington
J.F. Zhu, University of Washington
N. Ruzycki, University of Washington
Correspondent: Click to Email
The adsorption of Ca on the MgO(100) surface at 300 K has been studied using microcalorimetry, in combination with LEED, AES, ISS, work function and sticking probability measurements. The sticking probability of Ca on MgO(100) at 300 K is unity. The growth of Ca on MgO(100) follows the Stranski-Krastanov mode (i.e, 2D growth and thereafter followed by 3D islands). No ordered structure can be found in LEED during Ca adsorption. Initially, Ca adsorbs cationically at defect sites (~ 6% of the surface) with a high heat of adsorption (~ 425 kJ/mol). After these sites fill, Ca grows to complete the first layer with a heat of adsorption of 167 kJ/mol. Afterwards, it grows 3D islands and its heat approaches that of Ca's bulk heat of sublimation (179 kJ/mol). Ion sputtering of the MgO surface generates O vacancies which adsorb Ca with a heat of ~350 kJ/mol.