M2Ga(M=Cu,Ag,Au)二元合金小团簇的从头算研究

摘要

The ground electronic state and reasonable dissociation limits are correctlv determined based on Atomic and Molecular Reaction Statics and the Group Theory.The small coinage-metal gallium compounds M2Ga(M=Cu,Ag,Au)are studied at the perturbational estimate for triple excitations (CCSD(T)),the Mφller-Plesset second-order perturbationtheory (MP2) and the Hartree-Fock(HF)theoretical level with the effective small-core pseudopotential(LANL2DZ).It is found that the bend structure with C2v(2B2) symmetry for M2Ga(M=Cu,Ag,Au) is more stable than the linear structures and the duster of Au2Ga is the most stable cluster.The atomization energies are evaluated,which indicated that doping clusters M2Ga are more stable than the pure clusters M3.Moreover,the force constants and the vibrational frequencies of ground state structures are calculated.The electron correlation effects are investigated,which compact and stabilize the present species.%根据原子与分子反应静力学和群论理论推导出二元合金小团簇M2Ga(M=Cu,Ag,Au)的离解极限和基态电子态.采用量子力学从头算方法及小核实赝势和相应的基组,对二元合金小团簇M2Ga进行几何优化,得到M2Ga基态(2B2)为弯曲平面型结构,并与单元团簇M3(M=Cu,Ag,Au)相似.计算得到合金团簇比单元团簇稳定,其中Au2Ga体系最稳定.同时给出谐振频率、力常数,并且分析得到电子相关效应使得团簇更加紧凑、稳定性增强.