Physico-chemical nanomaterials science

Cluster modeling of amorphization paths in arsenic monosulfide driven by high-energy nanomilling
O. Shpotyuk1,2*, M. Hyla1, V. Boyko2
1 Institute of Physics of Jan Dlugosz University in Czestochowa 
13/15, al. Armii Krajowej, Czestochowa, 42200, Poland
2 Vlokh Institute of Physical Optics 
23, Dragomanov st., Lviv, 79005, Ukraine

Competitive amorphization scenarios possible in arsenic monosulphides AsS derived from directly-synthesized high-temperature β-As4S4 polymorph under different conditions of high-energy mechanical ball milling were identified with a help of ab-initio quantum-chemical cluster-modeling approach known as CINCA (the cation-interlinked network cluster approach) [1-3]. 
The geometrically-optimized configurations of cage-like As4S4 molecule and its different network-forming derivatives responsible for amorphization were simulated. These atomic clusters were reconstructed by breaking As4S4 molecule possessing D2d symmetry on distinct fragments linked with network by sulfur bridging chains S1/2…S1/2. The HyperChem Release 7.5 program package based on restricted Hartree-Fock self-consistent field method with split-valence double-zeta basis set and single polarization function 6-311G* was employed for final cluster energy calculations.
Full hierarchy of molecular-breaking events in arsenic monosulphide -As4S4 treated by high-energy mechanical milling consists of scenarios ensuring transition from As4S4 cage molecules to network clusters possessing different forming energies. Most possible are partially-polymerized single-broken As4S4 clusters keeping one hexagon and two adjacent pentagons in local atomic arrangement, which are responsible for uncontrolled amorphization in directly-synthesized -As4S4, while completely-polymerized triple-broken As4S4 clusters in chain-like configuration without ring entities are character for milling-driven amorphization in monoparticulate -As4S4- and biparticulate β-As4S4-Fe3O4-based composites.   

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