### Abstract

Size evolution of the equilibrium structures of Ar_{n}H _{2}O van der Waals clusters with n=1-14 has been investigated. Pairwise additive jntermolecular potential energy surfaces (IPESs) for Ar _{2}H_{2}O clusters were constructed from the spectroscopically accurate Ar-Ar and anisotropic 3D Ar-H_{2}O potentials. For each cluster size considered, we determined the global minimum of the respective IPES and several other lowest-lying Ar_{n}H_{2}O isomeric structures. This was accomplished by using simulated annealing followed by a direct minimization scheme. The minimum-energy structures of all Ar_{n}H _{2}O clusters considered in this work are fully solvated; up to n=12, the Ar atoms fill a monolayer around H_{2}O. For n=12, the optimal Ar_{12}H_{2}O structure has the Ar atoms arranged in a highly symmetrical icosahedron, with H_{2}O in its center. The icosahedral Ar_{12}H_{2}O structure is exceptionally stable; the energy gap separating it from the next higher n=12 isomer (289.55 cm^{-1}) exceeds that for any other cluster in this size range. The observed preference for solvated Ar_{n}H_{2}O structures was carefully analyzed in terms of the relative energetic contributions from Ar-Ar and Ar-H_{2}O interactions. For n≤9, the monolayer, cagelike geometries are favored primarily by providing optimal Ar-H_{2}O interactions, significantly larger than for alternative Ar_{n}H_{2}O structures. For n>9, the solvated Ar_{n}H_{2}O isomers offer the best Ar-Ar packing, in addition to the strongest total Ar-H_{2}O interactions. A detailed comparison was made with the minimum-energy structures of Ar_{n}HF clusters, determined by us recently [J. Chem. Phys. 100, 7166 (1994)], revealing interesting differences in the growth patterns of the optimal cluster structures.

Original language | English (US) |
---|---|

Pages (from-to) | 8310-8320 |

Number of pages | 11 |

Journal | The Journal of chemical physics |

Volume | 101 |

Issue number | 10 |

State | Published - 1994 |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*The Journal of chemical physics*,

*101*(10), 8310-8320.

**ArnH2O (n=1-14) van der Waals clusters : Size evolution of equilibrium structures.** / Liu, Suyan; Bacic, Zlatko; Moskowitz, Jules W.; Schmidt, Kevin E.

Research output: Contribution to journal › Article

*The Journal of chemical physics*, vol. 101, no. 10, pp. 8310-8320.

}

TY - JOUR

T1 - ArnH2O (n=1-14) van der Waals clusters

T2 - Size evolution of equilibrium structures

AU - Liu, Suyan

AU - Bacic, Zlatko

AU - Moskowitz, Jules W.

AU - Schmidt, Kevin E.

PY - 1994

Y1 - 1994

N2 - Size evolution of the equilibrium structures of ArnH 2O van der Waals clusters with n=1-14 has been investigated. Pairwise additive jntermolecular potential energy surfaces (IPESs) for Ar 2H2O clusters were constructed from the spectroscopically accurate Ar-Ar and anisotropic 3D Ar-H2O potentials. For each cluster size considered, we determined the global minimum of the respective IPES and several other lowest-lying ArnH2O isomeric structures. This was accomplished by using simulated annealing followed by a direct minimization scheme. The minimum-energy structures of all ArnH 2O clusters considered in this work are fully solvated; up to n=12, the Ar atoms fill a monolayer around H2O. For n=12, the optimal Ar12H2O structure has the Ar atoms arranged in a highly symmetrical icosahedron, with H2O in its center. The icosahedral Ar12H2O structure is exceptionally stable; the energy gap separating it from the next higher n=12 isomer (289.55 cm-1) exceeds that for any other cluster in this size range. The observed preference for solvated ArnH2O structures was carefully analyzed in terms of the relative energetic contributions from Ar-Ar and Ar-H2O interactions. For n≤9, the monolayer, cagelike geometries are favored primarily by providing optimal Ar-H2O interactions, significantly larger than for alternative ArnH2O structures. For n>9, the solvated ArnH2O isomers offer the best Ar-Ar packing, in addition to the strongest total Ar-H2O interactions. A detailed comparison was made with the minimum-energy structures of ArnHF clusters, determined by us recently [J. Chem. Phys. 100, 7166 (1994)], revealing interesting differences in the growth patterns of the optimal cluster structures.

AB - Size evolution of the equilibrium structures of ArnH 2O van der Waals clusters with n=1-14 has been investigated. Pairwise additive jntermolecular potential energy surfaces (IPESs) for Ar 2H2O clusters were constructed from the spectroscopically accurate Ar-Ar and anisotropic 3D Ar-H2O potentials. For each cluster size considered, we determined the global minimum of the respective IPES and several other lowest-lying ArnH2O isomeric structures. This was accomplished by using simulated annealing followed by a direct minimization scheme. The minimum-energy structures of all ArnH 2O clusters considered in this work are fully solvated; up to n=12, the Ar atoms fill a monolayer around H2O. For n=12, the optimal Ar12H2O structure has the Ar atoms arranged in a highly symmetrical icosahedron, with H2O in its center. The icosahedral Ar12H2O structure is exceptionally stable; the energy gap separating it from the next higher n=12 isomer (289.55 cm-1) exceeds that for any other cluster in this size range. The observed preference for solvated ArnH2O structures was carefully analyzed in terms of the relative energetic contributions from Ar-Ar and Ar-H2O interactions. For n≤9, the monolayer, cagelike geometries are favored primarily by providing optimal Ar-H2O interactions, significantly larger than for alternative ArnH2O structures. For n>9, the solvated ArnH2O isomers offer the best Ar-Ar packing, in addition to the strongest total Ar-H2O interactions. A detailed comparison was made with the minimum-energy structures of ArnHF clusters, determined by us recently [J. Chem. Phys. 100, 7166 (1994)], revealing interesting differences in the growth patterns of the optimal cluster structures.

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M3 - Article

VL - 101

SP - 8310

EP - 8320

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

ER -