A STRUCTURAL STUDY OF PD/CU(100) SURFACE ALLOYS

被引:34
作者
POPE, TD
VOS, M
TANG, HT
GRIFFITHS, K
MITCHELL, IV
NORTON, PR
LIU, W
LI, YS
MITCHELL, KAR
TIAN, ZJ
BLACK, JE
机构
[1] UNIV WESTERN ONTARIO,INTERFACE SCI WESTERN,LONDON N6A 5B6,ENGLAND
[2] UNIV BRITISH COLUMBIA,DEPT CHEM,VANCOUVER,BC V6T 1Z1,CANADA
[3] BROCK UNIV,DEPT PHYS,ST CATHARINES,ON L2S 3A1,CANADA
基金
加拿大自然科学与工程研究理事会;
关键词
LOW ENERGY ELECTRON DIFFRACTION (LEED); MEDIUM ENERGY ION SCATTERING (MEIS); MOLECULAR DYNAMICS; SURFACE STRUCTURE; THERMAL DESORPTION SPECTROSCOPY;
D O I
10.1016/0039-6028(95)00530-7
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The structures formed by one-half and one monolayer (ML) of Pd evaporated onto Cu(100) at 300 K were studied by low energy electron diffraction (LEED), medium energy ion scattering (MEIS), thermal desorption spectroscopy (TDS), and embedded atom method (EAM) calculations. In the half monolayer case, the LEED I(E) curves are consistent with the established c(2 x 2) surface alloy model. The MEIS data, however, suggest that a fraction of the Pd (similar to 1/4) is in ''second layer'' sites, in agreement with previous LEIS, TDS and XPS forward scattering measurements. The EAM simulations support the formation of alloy islands, providing a mechanism for the covering of some Pd atoms. As the deposition proceeds, however, this island formation is indicated to occur preferentially over clean copper. In the one monolayer case, a p(2 x 2)-p4g LEED pattern is observed. Analysis of the I(E) curves suggests that this arises from (100) Pd packed above the c(2 x 2) alloy. EAM calculations confirm the stability of this model. Evidence from MEIS and TDS, however, shows that the one monolayer surface as prepared in this work is inhomogeneous. c(2 x 2) and Cu rich surface domains exist in addition to those having the p4g Pd/c(2 x 2)PdCu structure.
引用
收藏
页码:79 / 91
页数:13
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