Abstract
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•The P dopants prefer substitution of Si atoms release P-doped clusters.•The P dopant tends to form three classical (2c–2e) SiP bonds.•Si4P−, Si3P2, Si7P− and Si6P2 have enhanced stability with electron shells of 22 and 34 electrons.•SiP2, Si2P− and Si3P− planar clusters are aromatic according to ring currents.•Bipyramid-like Si7, Si6P− and Si5P2 are aromatic in five-membered plane.•In their side-planes, Si7 and Si6P− are non-aromatic, and Si5P2 anti-aromatic.
The geometrical evolution, electronic structure and thermodynamic stability of a series of singly-doped SinP and doubly-doped SinP2 silicon clusters with n=1–10, in the neutral, cationic and anionic states were systematically investigated using DFT computations. The global minimum structures were identified using different search approaches. The isoelectronic structures including the neutral SinP, the cation Sin−1P2+ and the anion Sin+1− exhibit a similar shape. Structural evolution of doubly P-doped SinP2 was found to adopt a substitution mechanism rather than a caption pathway. Dissociation energies for various channels of SinP2 clusters point out that the fragmentations generating P2 atoms plus the corresponding Sin host is the most preferred process. The closed-shell species Si4P−, Si3P2, Si7P− and Si6P2 are found to have high thermodynamic stability with large binding energies and second-order difference energies. Their enhanced stability can be rationalized in terms of the Jellium shell model. The aromatic character was probed using the ring current maps of electron densities. The planar SiP2, Si2P− and Si3P− clusters feature an aromatic character, whereas only the five-membered plane of the bipyramid-like structures involving Si6P− and Si5P2 are locally aromatic.