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【目的】过渡族金属与铝之间的化学成键特性是化学与材料等领域的基础,对铝-4 d过渡族金属二聚体的物理性能进行研究。【方法】用密度泛函B3LYP方法计算铝-4 d过渡族金属二聚体的键长、振动频率、解离能、电离势、能隙和二极矩。【结果】对中性和荷电的二聚体,除AlMo、AlNb+和AlMo+外其键长从AlY到AlPd先减少后增加,解离能和振动频率的变化趋势与之相反。电离势随原子序数的递增先增加,在AlRh处达到极大值后减少。除AlTc的振动频率外,计算结果与已有的实验结果和其他的理论计算结果相符。计算结果还显示除AlCd外,前过渡族金属与铝的结合强度比后过渡族金属的结合要强。荷电二聚体的自旋多重度比相应的中性二聚体差±1。带正电的二聚体的键长比中性和带负电的二聚体的键长要长,荷电二聚体的解离能大于中性二聚体的解离能,解离方式为AlX+→X+Al+和AlX-→Al+X-。
【Objective】 The chemical bonding between transition metal and aluminum is the basis of chemistry and materials, and the physical properties of aluminum-4 d transition metal dimer are studied. 【Method】 The bond length, vibrational frequency, dissociation energy, ionization potential, energy gap and the second moment of the metal-4-d transition metal-aluminum dimers were calculated by the density functional theory B3LYP method. 【Result】 For neutral and charged dimers, the bond lengths of AlMo, AlNb + and AlMo + decreased firstly and then increased from AlY to AlPd, and the dissociation energy and vibration frequency tended to be opposite. The ionization potential first increases with atomic number increasing, then decreases after reaching the maximum at AlRh. Except the AlTc vibrational frequency, the calculation results are consistent with the existing experimental results and other theoretical calculations. The calculated results also show that except for AlCd, the bond strength of the former transition metal is stronger than that of the latter transition metal. Charged dimers have a spin multiplicity of ± 1 that of the corresponding neutral dimers. Bond length of the positively charged dimer is longer than that of the neutral and negatively charged dimer. The dissociation energy of the charged dimer is greater than the dissociation energy of the neutral dimer. The dissociation method is AlX + → X + Al + and AlX- → Al + X-.