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Theoretical studies of the angular distributions of oxygen atoms ejected from an ion bombarded c(2 × 2) overlayer of oxygen on Ni(001) II. Effect of interaction potential
A312 Surface Science 109 (1981) 419-434 North-Holland Publishing Company
419
SPIN P O L A R I Z A T I O N IN L O W - E N E R G Y E L E C T R O N D I F F R A C T I O N : SURFACE ANALYSIS OF Pt(111) R o l a n d F E D E R and H e r i b e r t P L E Y E R
Theoretische Festkdrperphysik, FB 1O, Universitat Duisburg GH, D-41O0 Duisburg, Germany and P e t e r B A U E R * and N o r b e r t M O L L E R **
Max-Planck-lnstitut ff~r Plasmaphysik, Euratom Association, SFB 128, D-8000 Miinchen, Germany Received 2 February 1981
Transverse and longitudinal spin polarization components arising in the diffraction of unpolarized low-energy electrons from Pt(111) have been studied as functions of energy and diffraction geometry. Experimental data measured by means of a Mott detector are in good agreement with theoretical results obtained by relativistic LEED calculations. A detailed investigation of the selective sensitivity of the calculated polarization profiles to the surface relaxation 612 and to various non-structural model features firstly supports an ion-core potential involving an energy-dependent exchange approximation (by discriminating against two band structure potentials), and secondly establishes the geometry of P t ( l l l ) as unreconstructed with a possible slight outward relaxation of the topmost atomic layer (612 = 0.5% -+ 1.0% of the bulk interlayer distance). A surface Debye temperature is found close to the bulk value 230 K.
Surface Science 109 (1981) 435 443 North-HoUand Publishing Company
435
T H E O R E T I C A L STUDIES OF THE A N G U L A R DISTRIBUTIONS OF OXYGEN A T O M S E J E C T E D F R O M A N ION
BOMBARDED c(2 × 2) O V E R L A Y E R
O F O X Y G E N ON Ni(001} II. E f f e c t o f i n t e r a c t i o n p o t e n t i a l Shukla K A P U R * a n d Barbara J. G A R R I S O N **
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Received 11 March 1981 A detailed molecular dynamics study has been performed in order to determine the influence of the interaction potential on the angles of ejection of oxygen atoms from an ion bombarded c(2 × 2) oxygen overlayer on Ni(001). The bonding site of the adsorbate appears to be the dominating factor which influences the angles of ejection. Changing the interaction potential affects the angular distribution similarly to varying the height of the adsorbate above the surface.
419
SPIN P O L A R I Z A T I O N IN L O W - E N E R G Y E L E C T R O N D I F F R A C T I O N : SURFACE ANALYSIS OF Pt(111) R o l a n d F E D E R and H e r i b e r t P L E Y E R
Theoretische Festkdrperphysik, FB 1O, Universitat Duisburg GH, D-41O0 Duisburg, Germany and P e t e r B A U E R * and N o r b e r t M O L L E R **
Max-Planck-lnstitut ff~r Plasmaphysik, Euratom Association, SFB 128, D-8000 Miinchen, Germany Received 2 February 1981
Transverse and longitudinal spin polarization components arising in the diffraction of unpolarized low-energy electrons from Pt(111) have been studied as functions of energy and diffraction geometry. Experimental data measured by means of a Mott detector are in good agreement with theoretical results obtained by relativistic LEED calculations. A detailed investigation of the selective sensitivity of the calculated polarization profiles to the surface relaxation 612 and to various non-structural model features firstly supports an ion-core potential involving an energy-dependent exchange approximation (by discriminating against two band structure potentials), and secondly establishes the geometry of P t ( l l l ) as unreconstructed with a possible slight outward relaxation of the topmost atomic layer (612 = 0.5% -+ 1.0% of the bulk interlayer distance). A surface Debye temperature is found close to the bulk value 230 K.
Surface Science 109 (1981) 435 443 North-HoUand Publishing Company
435
T H E O R E T I C A L STUDIES OF THE A N G U L A R DISTRIBUTIONS OF OXYGEN A T O M S E J E C T E D F R O M A N ION
BOMBARDED c(2 × 2) O V E R L A Y E R
O F O X Y G E N ON Ni(001} II. E f f e c t o f i n t e r a c t i o n p o t e n t i a l Shukla K A P U R * a n d Barbara J. G A R R I S O N **
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Received 11 March 1981 A detailed molecular dynamics study has been performed in order to determine the influence of the interaction potential on the angles of ejection of oxygen atoms from an ion bombarded c(2 × 2) oxygen overlayer on Ni(001). The bonding site of the adsorbate appears to be the dominating factor which influences the angles of ejection. Changing the interaction potential affects the angular distribution similarly to varying the height of the adsorbate above the surface.