Abstract:

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. 

Key words: Fe、Co、Ni/P binary cluster ions, Laser ablation, Laser photodissociation, TOF mass spectrometry