铁、钴、镍/磷二元团簇离子的形成与光解  

Formation and Photodissociation of Fe、Co、Ni/P Binary Cluster Ions

作　　者：韩春英[1] 邢小鹏[1] 张霞[1] 高振[1] 朱起鹤[1] 

机构地区：[1]中国科学院化学研究所分子科学中心分子反应动力学国家重点实验室,北京100080

出　　处：《物理化学学报》2000年第9期818-824,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金

摘　　要：利用激光直接溅射法产生了铁、钴、镍/磷二元团簇正负离子,并用串级飞行时间质谱仪研究了团簇离子的组份和激光光解规律.质谱研究表明,铁、钴、镍易与磷结合成簇,而且样品中磷含量的增加有助于大尺寸团簇离子的生成.当形成的团簇离子中含金属原子数目较少时,磷原子数目可在较大范围内变动,其中、、、(M=Fe、Co、Ni,n=2、3、4)团簇离子均具有较高的丰度；随着金属原子数目的增加,磷原子数目的变化范围相应地变窄,铁/磷趋向于形成原子数目比接近1∶1的团簇正离子,钴/磷则易形成富磷的团簇正离子,镍/磷团簇正离子中镍原子数远多于磷原子数,而这三种金属与磷形成的负离子团簇随样品中磷含量的增加由富金属簇向富磷簇转化.对部分团簇正离子的紫外激光光解表明,铁/磷团簇正离子中P4或P2光解时易剥落；而钴/磷、镍/磷团簇正离子的主要光解通道或是P4、P2的剥离,或是中性MnPm(m为偶数)碎片的失去.The binary cluster ions composed of Fe/P、 Co/P and Ni/P were generated by laser ablation.The composition of these binary cluster ions and the photodissociation of the cluster cations were studied by Tandem TOF MS.The experimental results show that sample with more phosphorus is favourable to the formation of large clusters.For clusters containing a few metal atoms the number of P atoms can vary over a wide range,and clusters,、 and (M=Fe、 Co、 Ni,n=2、 3、 4) are more abundant.In the clusters containing more metal atoms,the number of phosphorus atoms does not change greatly,and the atomic ratio of Fe and P tends to 1:1,the compositional Co/P cluster cations tend to be rich in phosphorus ,and contrarily,Ni/P cluster cations contain much more Ni atoms than P atoms.For cluster anions,the composition changes from metal rich to phosphorus rich with the increase of phosphorus in the sample.The photodissociation indicates that for Fe/P cluster cations,P2 or P4 was stripped easily,while for Co/P and Ni/P cluster cations,the main channel is P2 and P4 stripped,or neutral fragment MnPm(m is even) lost.

关 键 词：铁 钴 镍 磷 二元团簇离子 激光光解 激光溅射 

分 类 号：O657.63[理学—分析化学]