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| Formato: | Preprint |
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2025
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| Acceso en línea: | https://arxiv.org/abs/2506.05557 |
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| _version_ | 1866916781719814144 |
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| author | Ibrahim, Alexander Roy, Pierre-Nicholas |
| author_facet | Ibrahim, Alexander Roy, Pierre-Nicholas |
| contents | We present path integral Monte Carlo simulation results for the equation of state of solid parahydrogen between $ 0.024 \, {Å}^{-3} $ and $ 0.1 \, {Å}^{-3} $ at $ T = 4.2 \, $ K. The simulations are performed using non-additive isotropic ab initio two-body, three-body, and four-body potential energy surfaces (PES). We apply corrections to account for both the finite size simulation errors and the Trotter factorization errors. Simulations that use only the two-body PES during sampling yield an equation of state similar to that of simulations that use both the two-body and three-body PESs during sampling. With the four-body interaction energy, we predict an equilibrium density of $ 0.02608 \, {Å}^{-3} $, very close to the experimental result of $ 0.0261 \, {Å}^{-3} $. The inclusion of the four-body interaction energy also brings the simulation results in excellent agreement with the experimental pressure-density data until around $ 0.065 \, {Å}^{-3} $, beyond which the simulation results overestimate the pressure. These PESs overestimate the average kinetic energy per molecule at the equilibrium density by about $ 7 \% $ compared to the experimental result. Our findings suggest that, at higher densities, we require five-body and higher-order many-body interactions to quantitatively improve the agreement between the pressure-density curve produced by simulations, and that of experiment. Using the four-body PES during sampling at excessively high densities, where such higher-order many-body interactions are likely to be significant, causes an artificial symmetry breaking in the hcp lattice structure of the solid. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_05557 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Path-integral Monte Carlo simulations of solid parahydrogen using two-body, three-body, and four-body ab initio interaction potential energy surfaces Ibrahim, Alexander Roy, Pierre-Nicholas Chemical Physics We present path integral Monte Carlo simulation results for the equation of state of solid parahydrogen between $ 0.024 \, {Å}^{-3} $ and $ 0.1 \, {Å}^{-3} $ at $ T = 4.2 \, $ K. The simulations are performed using non-additive isotropic ab initio two-body, three-body, and four-body potential energy surfaces (PES). We apply corrections to account for both the finite size simulation errors and the Trotter factorization errors. Simulations that use only the two-body PES during sampling yield an equation of state similar to that of simulations that use both the two-body and three-body PESs during sampling. With the four-body interaction energy, we predict an equilibrium density of $ 0.02608 \, {Å}^{-3} $, very close to the experimental result of $ 0.0261 \, {Å}^{-3} $. The inclusion of the four-body interaction energy also brings the simulation results in excellent agreement with the experimental pressure-density data until around $ 0.065 \, {Å}^{-3} $, beyond which the simulation results overestimate the pressure. These PESs overestimate the average kinetic energy per molecule at the equilibrium density by about $ 7 \% $ compared to the experimental result. Our findings suggest that, at higher densities, we require five-body and higher-order many-body interactions to quantitatively improve the agreement between the pressure-density curve produced by simulations, and that of experiment. Using the four-body PES during sampling at excessively high densities, where such higher-order many-body interactions are likely to be significant, causes an artificial symmetry breaking in the hcp lattice structure of the solid. |
| title | Path-integral Monte Carlo simulations of solid parahydrogen using two-body, three-body, and four-body ab initio interaction potential energy surfaces |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2506.05557 |