Abstract
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.
| 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
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ArnH2O (n=1-14) van der Waals clusters : Size evolution of equilibrium structures. / Liu, Suyan; Bacic, Zlatko; Moskowitz, Jules W.; Schmidt, Kevin E.
In: The Journal of chemical physics, Vol. 101, No. 10, 1994, p. 8310-8320.Research output: Contribution to journal › Article
}
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 -