| Autor: |
Liu, Yu Yang Fredrik, Andrews, Bartholomew, Conduit, Gareth J. |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
J. Chem. Phys., 150(3):034104, Jan 2019 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1063/1.5070138 |
| Popis: |
We develop a formalism to directly evaluate the matrix of force constants within a Quantum Monte Carlo calculation. We utilize the matrix of force constants to accurately relax the positions of atoms in molecules and determine their vibrational modes, using a combination of Variational and Diffusion Monte Carlo. The computed bond lengths differ by less than 0.007{\AA} from the experimental results for all four tested molecules. For hydrogen and hydrogen chloride, we obtain fundamental vibrational frequencies within 0.1% of experimental results and ~10 times more accurate than leading computational methods. For carbon dioxide and methane, the vibrational frequency obtained is on average within 1.1% of the experimental result, which is at least 3 times closer than results using Restricted Hartree-Fock and Density Functional Theory with a Perdew-Burke-Ernzerhof (PBE) functional and comparable or better than Density Functional Theory with a semi-empirical functional. |
| Databáze: |
arXiv |
| Externí odkaz: |
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