固体表面吸附分子及其振动——Cu(100)-CO-c(2×2)体系的研究

ADSORBED MOLECULES ON SOLID SURFACE AND THEIR VIBRATIONS--STUDIES ON Cu (100)-CO-c (2×2) SYSTEM

近年来,人们对表面吸附问题进行了大量的研究。表面吸附可分为物理吸附及化学吸附,这两种吸附都能造成吸附分子振动谱的移动。化学吸附是由于吸附分子与固体表面层的原子或离子发生了电荷转移,使得分子的偶极矩改变,从而导致分子振动谱的移动。物理吸附取决于吸附分子间偶极子的耦和作用,对不同的固体表面、不同的吸附分子及不同的吸附结构,这两种吸附对频移的贡献是不一样的,通过研究这两种不同的吸附效应,就可获得各种固体表面的特殊信息。

A method is proposed to calculate vibrational frequencies and intensities of anadsorbed molecule system with P2mm or P4 symmetry. The method can be used ifthe system can be considered as a group of coupled oscillators with one freedom peroscillator. The stretch vibrations and lateral interactions of CO molecules adsorbed onCu(100) face are studied by means of this method. The calculated results show thatthe lateral force constants have a strong dependence on interaction range assumed.The size effects on vibrational frequencies of adsorbed system are also examined.The results given here are to be expected.