AlB_n^+(n=2-10)团簇结构和红外振动光谱研究

Theoretical Study of Structure and Infrared Vibration Spectra about AlB_n^+(n=2-10) clusters

用密度泛函理论的B3LYP方法在6-311G(d)水平上对AlB+n(n=2-10)团簇几何结构、稳定性、电子结构和成键特性进行了系统理论研究,得到了AlB+n(n=2-10)团簇的最稳定结构.结果表明,硼原子间容易聚集,铝原子处于整个硼原子集团的外围.与相应中性AlBn团簇相比,Al-B键作用变弱,使正价团簇(n=6和10除外)结构变化较大;对AlB+n(n=2-10)和相应中性团簇能隙的计算分析表明,AlB+n团簇的稳定性有所增强,其中AlB+3、AlB+5和AlB+8团簇尤为显著;通过对最稳定构型红外振动光谱的研究分析表明,硼原子间对称或非对称振动、铝原子不动的振动模式更容易出现较强谱峰,即硼原子间更容易成键.

The geometrical structures,relative stabilities,electronic structures and bonding properties of AlB＋n（n = 2-10） clusters have been investigated by using the density functional theory at the level B3LYP/6-311G（d）.With the most stable structures obtained,it shows that the boron atoms are more likely to get together,remaining the Al atom lying around the boron-atom group.Compared to the neutral clusters,the effect of Al-B bonds becomes weaker,which leading to a relative bigger change of geometry to neutral clusters when n=2-4 and n=7-10.Via calculating the energy gap for both positive charged and neutral clusters,we found that the stability of AlBn＋（n = 2-10） clusters enhances,especially for AlB＋3,AlB＋5 and AlB＋8 clusters.Infrared vibration spectra of the most stable structures are also investigated.The vibration mode with symmetrical or no-symmetrical vibration between B atoms and fixed Al atom are easier to perform a more intense spectral peak.This result indicates that the B atoms should be preferential to bond.