Molecular manganese sulfide clusters formed by laser ablation

Abstract

Laser ablation of solid MnS yields in the gas phase polysulfane cations [MnS _n ] ⁺ (4 ⩽ n ⩽ 11), and anionic clusters [Mn _x S _x ] ^- and [Mn _x S _x+1 ] ^- (2 ⩽ x ⩽ 22), together with clusters [Mn _x S _x O] ^- (4 ⩽ x ⩽ 22) formed from adventitious water. These ions were detected and investigated further by Fourier-transform ion cyclotron resonance mass spectrometry. There are no major discontinuities in abundance or especially stable structures in the series [Mn _x S _x ] ^- and [Mn _x S _x+1 ] ^- . There are some differences in the distributions of ions formed by the pink and green forms of solid MnS, with the pink form generating more sulfur vapour and polysulfane cations, and the green form more suitable for the formation of cluster anions. The cations [MnS _n ] ⁺ lose S ₂ on collisional activation. The cluster anions [Mn _x S _y ] ^- are generally unreactive and not oxidised by N ₂ O, but on reaction with H ₂ S (g) they undergo protonation or add one or two S atoms to form also the new products [Mn _x S _x+2 ] ^- (4 ⩽ x ⩽ 8). The compositions [Mn _x S _x ] ^- and [Mn _x S _x+1 ] ^- represent a well defined region of stability for anions, and for the neutral clusters from which they are believed to be formed by electron attachment.