Cluster Modeling of Network-Forming Amorphization Pathways in AsxS100−x Arsenicals (50 ≤ x ≤ 57) Diven by Nanomilling

• Published in: Journal of cluster science Vol. 33; no. 4; pp. 1525 - 1541
• Main Authors: Shpotyuk, Oleh, Hyla, Malgorzata, Shpotyuk, Yaroslav, Balitska, Valentina, Kozdras, Andrzej, Boyko, Vitaliy
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2022; Springer Nature B.V
• Subjects: Amorphization; Arsenic; Catalysis; Chemical bonds; Chemistry; Chemistry and Materials Science; Coordination numbers; Crystallization; Energy; Glass; Inorganic Chemistry; Mechanical milling; Nanochemistry; Original Paper; Physical Chemistry; Potential energy; Pyramids; Quantum chemistry; Stoichiometry; Triangles; quantum-chemical modeling; Arsenicals; Amorphization; Molecular cluster; Nanomilling
• ISSN: 1040-7278; 1572-8862
• DOI: 10.1007/s10876-021-02077-6

Complete hierarchy of network amorphization scenarios initiated in As x S 100-x nanoarsenicals within As 4 S 4 -As 4 S 3 cut-Sect. (50 ≤ x ≤ 57) is reconstructed employing materials-computational approach based on ab-initio quantum-chemical modeling code (CINCA). Under nanostructurization due to high-energy mechanical milling, the inter-crystalline transformations to nanoscopic β-As 4 S 4 phase accompanied by appearance of covalent-network amorphous matrix are activated. General amorphization trend under nanomilling obeys tending from molecular cage-like structures to optimally-constrained covalent-bonded networks compositionally invariant with parent arsenical. The contribution of amorphization paths in nanoarsenicals is defined by their chemistry with higher molecular-to-network barriers proper to As 4 S 3 -rich alloys. The generated amorphous phase is intrinsically decomposed, possessing double- T g relaxation due to stoichiometric (x = 40) and non-stoichiometric (x > 40) sub-networks, which are built of AsS 3/2 pyramids and As-rich arrangement keeping (i) two separated As-As bonds derived from realgar-type molecules, (ii) two neighboring As-As bonds derived from pararealgar-type molecules or (iii) three neighboring As-As bonds in triangle-like geometry derived from dimorphite-type molecules. Compositional invariance of nanoamorphous phase is ensured by growing sequence of network-forming clusters with average coordination numbers Z in the row (As 2 S 4/2, Z  = 2.50) – (As 3 S 5/2 , Z  = 2.55) – (As 3 S 3/2 , Z  = 2.67). Diversity of main molecular-to-network amorphizing pathways in nanoarsenicals is reflected on the unified potential energy landscape specified for boundary As 4 S 4 and As 4 S 3 components.