ADSORPTION OF HYDROGEN ON BE(0001) SURFACES

被引：33

作者：

LOSSEV, V ^{[1
]}

KUPPERS, J ^{[1
]}

机构：

[1] UNIV BAYREUTH,W-8580 BAYREUTH,GERMANY

来源：

SURFACE SCIENCE | 1993年 / 284卷 / 1-2期

关键词：

D O I：

10.1016/0039-6028(93)90535-R

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：

Molecular hydrogen does not adsorb on Be(0001) surfaces, suggesting activated adsorption, as was found with other s-metal/H adsorption systems. The present study investigates the interaction of thermal H atoms with clean and oxygen-covered Be(0001) surfaces using thermal desorption spectroscopy, TDS. Atomic hydrogen adsorbs at Be and oxygen-covered Be, at clean Be surfaces with a sticking coefficient in the order of unity. Molecular H-2 desorption is observed to follow a second-order rate at least in a restricted low coverage regime. Desorption is observed around 320 (O covered Be) and 450 K (clean Be) with activation energies of 14 and 20 (+/- 2) kcal/mol, respectively. Desorption frequency factors are obtained in the range 10(-4) cm2/s. At higher coverages the apparent desorption kinetics is different at Be and O-covered Be surfaces. The adsorption is endothermic with respect to H-2/Be and above 300 K hydrogen absorption in Be occurs competitively to desorption. Absorbed H in the Be bulk is outgassed with a complicated kinetics, however, H diffusion in Be seems not to limit H outgassing from Be. The formation of a Be-hydride is not observed.

引用

页码：175 / 185

页数：11

共 28 条

[1] DEUTERIUM PERMEATION AND DIFFUSION IN HIGH-PURITY BERYLLIUM [J].