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首页> 外文期刊>The Journal of Chemical Physics >A molecular beam study of nonlinearity in the CO-induced surface restructuring of Ir{100}
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A molecular beam study of nonlinearity in the CO-induced surface restructuring of Ir{100}

机译：CO诱导的Ir {100}表面重组中的非线性分子束研究

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The kinetics of CO chemisorption on both the (1 x 5) and (1 x 1) surfaces of Ir{100}, including the CO-induced surface restructuring process, have been studied by measuring the sticking probability as a function of the surface temperature and beam flux. Due to competition between desorption from the (1 x 5) phase and growth of(1 x 1) islands, the sticking probability on the initial (1 x 5) surface is strongly flux-dependent at surface temperatures T-s in the range 480 less than or equal to T(s)less than or equal to 510 K. It is shown that this is due to a strongly nonlinear dependence of the (1 x 1) growth rate on the local CO coverage on the (1 x 5) substrate, with an apparent reaction order of around 5. Desorption energies and pre-exponentials of desorption for CO from both the (1 x 1) and (1 x 5) surfaces have been determined by means of a modified lifetime measurement technique. Equilibrium coverages as well as isothermal desorption rates of CO were determined for both surface phases. The zero coverage desorption energy of CO from the (1 x 1) substrate is 196 +/- 5 kJ/mol and from the (1 x 5) surface it is around 150 kJ/mol. This difference in adsorption energies is the driving force for the CO-induced (1 x 5) to (1 x 1) phase transition. TEAS data show that the local CO coverage on the growing (1 x 1) islands during the phase transformation is 0.5 ML. (C) 1998 American Institute of Physics. [S0021-9606(98)70348-4]. [References: 29]
机译：通过测量粘附概率随表面温度的变化，研究了Ir {100}在（1 x 5）和（1 x 1）表面上的CO化学吸附动力学，包括CO诱导的表面重构过程。和光束通量。由于（1 x 5）相的解吸与（1 x 1）岛的生长之间的竞争，在表面温度Ts小于480的范围内，初始（1 x 5）表面上的粘附概率与通量密切相关。或等于T（s）小于或等于510K。这表明这是由于（1 x 1）生长速率对（1 x 5）基板上局部CO覆盖率的强烈非线性依赖性所致，表观反应阶数约为5。已经通过改进的寿命测量技术确定了从（1 x 1）和（1 x 5）表面脱附的CO的脱附能和预指数。确定了两个表面相的平衡覆盖率以及等温脱附率。从（1 x 1）基板的CO的零覆盖解吸能量为196 +/- 5 kJ / mol，从（1 x 5）表面的CO的零覆盖解吸能量约为150 kJ / mol。吸附能的这种差异是CO诱导的（1 x 5）到（1 x 1）相变的驱动力。 TEAS数据显示，在相变过程中，正在增长的（1 x 1）岛上的局部CO覆盖率为0.5 ML。 （C）1998美国物理研究所。 [S0021-9606（98）70348-4]。 [参考：29]

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