Benchmark Structures and Binding Energies of Small Water Clusters with Anharmonicity Corrections
The Journal of Physical Chemistry A
For (H2O)n where n = 1–10, we used a scheme combining molecular dynamics sampling with high level ab initio calculations to locate the global and many low lying local minima for each cluster. For each isomer, we extrapolated the RI-MP2 energies to their complete basis set limit, included a CCSD(T) correction using a smaller basis set and added finite temperature corrections within the rigid-rotor-harmonic-oscillator (RRHO) model using scaled and unscaled harmonic vibrational frequencies. The vibrational scaling factors were determined specifically for water clusters by comparing harmonic frequencies with VPT2 fundamental frequencies. We find the CCSD(T) correction to the RI-MP2 binding energy to be small (
Temelso, Berhane; Archer, Kaye A.; and Shields, George C.. "Benchmark Structures and Binding Energies of Small Water Clusters with Anharmonicity Corrections." The Journal of Physical Chemistry A 115, no. 43 (2011) : 12034-12046.