NONADIABATIC EFFECTS IN HYDROGEN DIFFUSION IN METALS
NONADIABATIC EFFECTS IN HYDROGEN DIFFUSION IN METALS
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DOI：
10.1103/physrevlett.68.3444
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发表时间：
1992-06-08
影响因子：
8.6
通讯作者：
WAHNSTROM, G
中科院分区：
文献类型：
--
作者：
LI, YG;WAHNSTROM, G
采用基于嵌入原子方法的势函数，对氢在Pd中的扩散过程进行了分子动力学模拟。发现单一绝热Born-Oppenheimer势能面不能再现中子散射研究中得到的准弹性峰的波矢依赖性。通过引入传导电子之间的电子-空穴对激发的耦合，得到了与实验接近的结果。这表明，在某些情况下，为了正确地描述氢在金属中的扩散运动，必须超越玻恩-奥本海默近似。
Molecular dynamic simulations for hydrogen diffusion in Pd are performed, using a potential based on the embedded-atom method. It is found that a single adiabatic Born-Oppenheimer potential energy surface cannot reproduce thc wave-vector dependence of the quasielastic peak obtained in neutron scattering studies. By incorporating coupling to low-lying electron-hole-pair excitations among the conduction electrons close agreement with the experimental result is obtained. This shows that in some cases one has to go beyond the Born-Oppenheimer approximation in order to characterize correctly the diffusive motion of hydrogen in metals.