Medium-sized phosphorus cluster cations P+ 2m+1 (6 ≤ m ≤ 32) studied by collision-induced dissociation mass spectrometry.

Medium-sized phosphorus cluster cations were generated by laser ablation of red phosphorus and investigated by the method of collision-induced dissociation mass spectrometry. Experimental results show that the primary dissociation channels of phosphorus cluster cations of P(+) 2m+1 (6 ≤ m ≤ 11) are all characterized by the loss of P4 unit. For larger cluster cations, their dissociation pathways were more complex. For those magic cations of P(+) 8k+1 observed previously, their dissociation pathways progressively change from the loss of P4 unit (for k = 3) to the loss of P8 unit (for k = 4, 5). A new dissociation pathway characterized by the loss of P10 unit was also indentified for larger cations of P(+) 8k+1 (6 ≤ k ≤ 8). Theoretical calculation also shows that, for cations of P(+) 2m+1 (4 ≤ m ≤ 10), the dissociation channel characterized by the loss of P4 unit is more energetically favorable than other dissociation channels, which is in good agreement with the experimental results.