Imam Mohammad ibn Saud Islamic University

This study examines the interrelation among gold, oil, and cryptocurrency markets and their implications for economic growth in the context of geopolitical turmoil. Employing panel data from 2000 to 2023 of exporter, importer, and mixed economies, we employ Nonlinear Autoregressive Distributed Lag (NARDL) and Panel Vector Autoregression (PVAR) to ascertain asymmetric as well as dynamic relations. Evidence shows that oil and gold price shocks exert significant effects on growth with geopolitical risk increasing volatility, while cryptocurrencies are heterogeneously resilient in panels. The results provide fresh evidence of cross-asset linkages, risk transmission mechanisms, and provide policy implications for policymakers and investors under volatile geopolitical environments.

An integrated computational study combining density functional theory and molecular dynamics simulation were performed to elucidate the adsorption mechanism of acetaminophen on Copper Oxide (CuO) and Zinc Oxide (ZnO) nanoparticles in aqueous media. The global electronic descriptors of the optimized adsorption complexes show clear differences. CuO/acetaminophen exhibits E HOMO = −7.33, E LUMO = −6.87 (ΔEgap = 0.461 eV), low chemical hardness (η = 0.23), high softness (S = 4.33) and very large electrophilicity (ω = 109.35). In contrast, ZnO/acetaminophen has E HOMO = −5.76, E LUMO = −0.92 (ΔE gap = 4.84 eV), η = 2.42, S = 0.41 and ω = 2.30, indicating CuO as a much stronger electron acceptor. Fukui and MEP maps identify the carbonyl (O11) and phenolic (O7) oxygens as primary donors (O11 f − = 0.1398, f + = 0.0866, f° = 0.2264). NBO analysis reveals larger donor → acceptor stabilization for CuO (E 2 = 37.7 kcal/mol) than ZnO (E 2 = 8.5 kcal/mol), consistent with significant LP(O/N) → metal charge-transfer on CuO. MD simulations corroborate stronger binding on CuO (E ads = −276 to −277.6 kcal/mol) than ZnO (−219 to −230 kcal/mol) over 290-318 K. Energy decomposition shows that (E deformation = −182 to −186 kcal/mol) dominates stabilization in both systems, while CuO displays a much larger E rigid (−93 to −95 kcal/mol) than ZnO (−36 to −45 kcal/mol). RDFs and non-bonded decomposition indicate short range, electrostatic coordination bonding on CuO (1.9–2.0 Å), and longer-range, dispersion H-bonding dominated contacts on ZnO (> 3.5 Å). These descriptors support a mechanism in which CuO favors charge transfer coordination (chemisorption), while ZnO favors relaxation assisted physisorption. This could guide the development of practical adsorbents for water treatment. CuO for strong sequestration and ZnO for reversible capture. • Mechanistic Contrast. • Electronic Structure Drivers. • Primary Adsorption Sites. • Stronger Binding to CuO. • Charge Transfer Evidence. • Practical Implications for Water Treatment.