离子型氢化物MH(M=Li,Na,K和Rb)的分子形貌的研究

Study on the molecular face of ionic hydrides MH(M=Li,Na,K and Rb)

采用MP2/6-311++G(3df,3pd)方法(RbH使用MP2/CEP-121G方法)优化得到了离子氢化物MH(M=Li,Na,K和Rb)的几何构型,计算了分子的第一电离能.使用MELD精密从头计算中的CISD/6-311++G**方法(RbH使用CISD/3-21G),并结合我们自编的分子形貌程序,描绘出了离子氢化物的分子形貌.讨论了电离能、极化率(仭)与分子轮廓的关系,得到了由Li H到RbH,离子化合物的电离能依次减小,极化率依次增大,轮廓依次增大的变化规律.定义和计算了MH氢化物的内禀特征参数,比较了化合物中的氢和碱金属端轮廓值与孤立原子的相对大小,发现了离子化合物MH中H原子端膨胀,金属原子端收缩的现象.通过这些分子的分子形貌研究,将为进一步探讨和认识这些氢化物及其团簇的结构和性质,提供一种直观的工具.

The geometries were optimized and their ionization energy and polarizability were calculated with MP2/6-311＋＋G（3df,3pd） for LiH,NaH and KH hydrides in the ground state,whereas with MP2/CEP-121G for RbH molecule.The molecular faces of LiH,NaH and KH hydrides were depicted by using the CISD in MELD package combination with our in-house MF program with the 6-311＋＋G（d,p） basis set,but for RbH with 3-21G.The relationship between the first ionization energies,mean polarizability and contours of these hydrides was explored.It can be obtained that the ionization energies have in turn decreased from LiH to RbH hydrides,and polarizability in turn increased,whereas their contours in turn have augmented.The parameters of the intrinsic characteristic contours of atomic regions in MH hydrides were calculated.The parameters of the regions of H and metal atoms were compared with the radius of corresponding isolated atoms.For these hydrides,their H atomic regions have expanded,whereas their metal atomic regions have shrunk.The molecular faces of these hydrides will provide us a visual tool to further explore and understand the structures and quantities of these hydrides and their clusters.