惰性元素化合物相对论效应的研究 Ⅰ.相对论效应的计算

A Study on Relativistic Fffect of Rare Gas Compounds Ⅰ. Calculation-of Relativistic Effect

分子形成中的相对论效应定义为ΔE_R=(E_R^M-E_N^M)-sum from A to(E_R^A-_N^A)。用相对论电荷迭代EHT程序ITEREX计算了惰性元素氟化物XeF_2,XeF_4,XeF_6,KrF_2和RnF_2的相对论效应,分别为-72.91,-160.34,-281.82,-25.44和-220.7 kJ·12mol^(-1)。惰性元素化合物的相对论效应都是负值,使分子趋于稳定。还计算了IF和CsF的相对论效应,分别是10.68和17.42kJ·mol^(-1),均为正值,使分子能量升高。证实了相对论效应在惰性元素化合物中的重要作用。

The relativistic effect is defined as ΔE_R=E_R^M-E_N^M-()(E_R^A-E_N^A), in which E_R^M is molecular energy obtained from relativistic caloulation, E_N^M is molecular energy obtained from nonrelativistic calculation, E_R^A and E_N^A are atomic energies obtained from relativistic and nonrelastivitic calonlations respectively, the summing is over the atoms of which the molecule consists. Series of rare gas fluorides XeF_2, XeF_4, XeF_6, KrF_2, and RnF_2 have been calculated by means of relativistic charge-consistent extended Huckel program ITEREX. These relativistic effects are -72.91,-160.34, -281.82, -25.44, and -220.7kJ·mol^(-1) respectively, they are all negative and make the molecules stable. The relativistic effects of moleoules IF and CsF are 10.68 and 5.416kJ·mol^(-1), which make the molecular energies increase. The results of our calculations prove that the relativistic effect plays an important role in bonding of rare gas compounds.