### Abstract

The structure of liquid ammonia at T=273 K has been studied using classical ab initio molecular dynamics, classical molecular dynamics, and the path-integral molecular dynamics methods. The three different types of calculation are employed to generate new insights into the ability of theoretical methods to model liquid ammonia effectively. Thus, the limitations of using classical nuclei, simple point charge models, small systems, and gradient corrected density functional theory are assessed through a comparison of the results of the different types of calculations to each other and recent experiments in a consistent manner. Briefly, the experimental intermolecular quantum structure is very well reproduced by the classical approximation while the intramolecular classical and quantum structures exhibit large deviations. The intermolecular ab initio partial radial structure factors of liquid ammonia and the associated radial distribution functions are in better agreement with experiment than the empirical models. However, the empirical models also perform reasonably well.

Original language | English (US) |
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Pages (from-to) | 1096-1103 |

Number of pages | 8 |

Journal | Journal of Chemical Physics |

Volume | 111 |

Issue number | 3 |

State | Published - Jul 15 1999 |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*Journal of Chemical Physics*,

*111*(3), 1096-1103.

**Simulation studies of liquid ammonia by classical ab initio, classical, and path-integral molecular dynamics.** / Diraison, M.; Martyna, G. J.; Tuckerman, Mark.

Research output: Contribution to journal › Article

*Journal of Chemical Physics*, vol. 111, no. 3, pp. 1096-1103.

}

TY - JOUR

T1 - Simulation studies of liquid ammonia by classical ab initio, classical, and path-integral molecular dynamics

AU - Diraison, M.

AU - Martyna, G. J.

AU - Tuckerman, Mark

PY - 1999/7/15

Y1 - 1999/7/15

N2 - The structure of liquid ammonia at T=273 K has been studied using classical ab initio molecular dynamics, classical molecular dynamics, and the path-integral molecular dynamics methods. The three different types of calculation are employed to generate new insights into the ability of theoretical methods to model liquid ammonia effectively. Thus, the limitations of using classical nuclei, simple point charge models, small systems, and gradient corrected density functional theory are assessed through a comparison of the results of the different types of calculations to each other and recent experiments in a consistent manner. Briefly, the experimental intermolecular quantum structure is very well reproduced by the classical approximation while the intramolecular classical and quantum structures exhibit large deviations. The intermolecular ab initio partial radial structure factors of liquid ammonia and the associated radial distribution functions are in better agreement with experiment than the empirical models. However, the empirical models also perform reasonably well.

AB - The structure of liquid ammonia at T=273 K has been studied using classical ab initio molecular dynamics, classical molecular dynamics, and the path-integral molecular dynamics methods. The three different types of calculation are employed to generate new insights into the ability of theoretical methods to model liquid ammonia effectively. Thus, the limitations of using classical nuclei, simple point charge models, small systems, and gradient corrected density functional theory are assessed through a comparison of the results of the different types of calculations to each other and recent experiments in a consistent manner. Briefly, the experimental intermolecular quantum structure is very well reproduced by the classical approximation while the intramolecular classical and quantum structures exhibit large deviations. The intermolecular ab initio partial radial structure factors of liquid ammonia and the associated radial distribution functions are in better agreement with experiment than the empirical models. However, the empirical models also perform reasonably well.

UR - http://www.scopus.com/inward/record.url?scp=0000577737&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000577737&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0000577737

VL - 111

SP - 1096

EP - 1103

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 3

ER -