Computing Free Energies of Hydroxylated Silica Nanoclusters: Forcefield versus Density Functional Calculations
| Autor: | Antoni Macià Escatllar, Piero Ugliengo, Stefan T. Bromley |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Internal energy
Chemistry nanoclusters Thermodynamics Parameterized complexity 02 engineering and technology hydroxylated silica free energy density functional theory forcefields 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Nanoclusters Inorganic Chemistry Hydroxylation chemistry.chemical_compound Computational chemistry Thermal Free energies Density functional theory 0210 nano-technology Electronic energy |
| Zdroj: | Inorganics; Volume 5; Issue 3; Pages: 41 |
| ISSN: | 2304-6740 |
| DOI: | 10.3390/inorganics5030041 |
| Popis: | We assess the feasibility of efficiently calculating accurate thermodynamic properties of (SiO2)n·(H2O)m nanoclusters, using classical interatomic forcefields (FFs). Specifically, we use a recently parameterized FF for hydroxylated bulk silica systems (FFSiOH) to calculate zero-point energies and thermal contributions to vibrational internal energy and entropy, in order to estimate the free energy correction to the internal electronic energy of these nanoclusters. The performance of FFSiOH is then benchmarked against the results of corresponding calculations using density functional theory (DFT) calculations employing the B3LYP functional. Results are reported first for a set of (SiO2)n·(H2O)m clusters with n = 4, 8 and 16, each possessing three different degrees of hydroxylation (R = m/n): 0.0, 0.25 and 0.5. Secondly, we consider five distinct hydroxylated nanocluster isomers with the same (SiO2)16·(H2O)4 composition. Finally, the free energies for the progressive hydroxylation of three nanoclusters with R = 0–0.5 are also calculated. Our results demonstrate that, in all cases, the use of FFSiOH can provide estimates of thermodynamic properties with an accuracy close to that of DFT calculations, and at a fraction of the computational cost. |
| Databáze: | OpenAIRE |
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