钇团簇吸附氢分子的理论研究

Theoretical study of H_2 adsorbed on Y_n(n=1-12) clusters

运用密度泛函理论,研究了H2分子在Yn(n=1-12)团簇表面的吸附.结果表明:一般情况下,两个H原子倾向于对称地吸附于三个Y原子的面位中央,H-H键断裂,为典型的解离性吸附.多数情况下,H2吸附并未使主团簇基态结构发生明显改变.YnH2体系表现出了较大的的吸附能,且吸附能值随尺寸增加而增大.分裂能和能量二阶差分均随尺寸变化表现出了奇偶振荡效应.Y6H2不仅稳定性最好,而且具有很好的吸附强度,吸附能为3.012eV.

Density functional theory （DFT） has been used to study the adsorption of H2 on Yn（n=1-12） clusters .The results show that two hydrogen atoms tend to be absorbed on the center of the face of three Y atoms symmetrically ,which is actually the typically dissociative adsorption due to the fracture of H-H bond .In most cases ,the basic framework of the host Yn clusters can not be changed by the adsorp-tion of H2. The YnH2 clusters exhibit larger adsorption energy ,which also increases continuously as the enlargement of the cluster size .Both dissociation energy and second -order energy differences exhibits the odd-even oscillation simultaneously .Y6 H2 has not only the highest stability ,but also the larger ad-sorption energy （3.012 eV） .