Comparative Performance of MP2 and CCSD Methods in Predicting the Nanothermodynamics of Doped ZNO Clusters
Year: 2026
Type: preprint
Abstract: This study provides a computational evaluation of the thermodynamic properties of doped ZnO molecular nanoclusters by evaluating the divergence between the Coupled Cluster with Singles and Doubles (CCSD) method and second-order Møller–Plesset (MP2) perturbation theory. We quantify a force-constant stiffness artifact in MP2, which systematically overestimates the fundamental vibrational frequency of ZnO by approximately 19.2%. This error scales with geometric complexity, inducing a systematic deviation in the Zero-Point Vibrational Energy (ZPVE) exceeding 1.7 kJ/mol for heavily doped configurations such as ZnO/CdTe. Evaluating thermodynamic profiles from 0.1 K to 6000 K reveals that the expansion of vibrational degrees of freedom in doped clusters yields dense, low-frequency manifolds that drive substantial entropic stabilization (-TS) at elevated temperatures (>1000 K). While partition functions were mapped up to 6000 K to observe asymptotic mathematical behaviour, we note that above 1500 K, anharmonicity limits our data to an idealized harmonic upper bound. Our result establishes a vital predictive baseline for complex doped clusters where precise experimental calorimetry is absent, providing the rigorous accuracy required to parameterize dispersion-corrected Density Functional Theory (DFT-D) for future mesoscale nanomaterial design.
Source: Research Square
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212428153