ORTHO-PARA H2 CONVERSION ON A COLD AG(111) METAL-SURFACE

被引:48
作者
ILISCA, E [1 ]
机构
[1] OSAKA UNIV,EXTREME MAT RES CTR,TOYONAKA,OSAKA 560,JAPAN
关键词
D O I
10.1103/PhysRevLett.66.667
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Electron-energy-loss experiments of h2 physisorbed on noble metals at low temperature indicate that the ortho-para conversion rate is 2 orders of magnitude faster on a Ag(111) surface than on a Cu(100) one. We suggest a process in which a metal electron is virtually transferred back and forth from a surface band to the molecule antibonding orbital, the ortho-para energy being dissipated by metal (electron-hole) triplet pairs. The ortho-para rates are about 1 min on Ag(111) and 1 h on Cu(100), in agreement with experimental data. This large difference does not characterize Ag and Cu, but is inherent to different surface orientations.
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页码:667 / 670
页数:4
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