Abstract: Au_nP_m^±(m=1-21, n=1-20) and (n=1-15, m=1-13) were generated by laser ablating the mixture of gold and red phosphorus powders, and their mass spectra were recorded by a time-of-flight mass spectrometer.The mass spectra were analyzed and the mass distributions of the binary cluster ions were studied as a function of the cluster size.The relative signal intensities of most observed cluster ions exhibit even/odd alternation.With increase of the cluster size, increment of clustering phosphorus atoms, m, is much less than that of clustering gold atoms, and the distribution of m for the same m of Au_nP_m^± tends to be narrower.The results suggest that, at least in the larger cluster ions, the clustering gold atoms are bonded together to form the core of the clusters.

Key words: Clusters, Gold, Phosphorus, Mass spectrometry, Laser ablation