Year: 2018
Type: article
Abstract: The rich potential energy surface of the water undecamer (H2O)11 was explored with a basin hopping algorithm using a TIP4P potential and other methods followed by extensive ab initio MP2 minimizations and CCSD(T) corrections. This protocol yielded 17, 66, and 125 distinct isomers within 0.5, 1.0, and 2.0 kcal mol–1 of the complete basis set CCSD(T) global minimum, respectively. These isomers were categorized into 15 different families based on their oxygen framework and hydrogen bonding topology. Determination of the global minimum proved challenging because of the presence of many nearly isoenergetic isomers. The predicted global minimum varied among ab initio methods, density functionals, and model potentials, and it was sensitive to the choice of energy extrapolation schemes, higher-order CCSD(T) corrections, and inclusion of zero-point vibrational energy. The presence of a large number of nearly degenerate structures and the isomerization between them has manifested itself in the anomalous broadening of the heat capacity curve of the undecamer in simulations around the melting region.
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1286236842, RUI: Thermodynamics of Nucleation: From Water to Atmospheric Aerosols, G1863003419, G2494066659, MRI: Acquisition of High Performance Computers for the Molecular Education and Research Consortium in Undergraduate computational chemistRY (MERCURY), G2909742425, G3083819904, G3689434148, G3892351006, G4501827968, G4667759259, G498139845, G5094606986, G6652958823, RUI: Thermodynamics of Secondary Aerosol Formation: The Role of Binary and Ternary Nucleation, G8613421693, G969889393
OpenAlex ID: W2783903474