The Journal of Physical Chemistry A · 2005 · 21 citations · 23 references
Natural SciencesChemistryPhysicsPhysical ChemistryQuantum ChemistryTheoretical ChemistryAb Initio MethodsChemical ThermodynamicsMolecular Orbital TheoryMolecular VibrationPotential Energy SurfacesVibrational StructureAb Initio CalculationsAb Initio Potential Energy SurfacesHarmonic Oscillator ApproximationIntermolecular Potential Energy SurfacesMolecular Partition FunctionsMolecular Potential Energy SurfacesPotential Energy Surface AnalysisVibrational Energy Levels
The intermolecular potential energy surface of O(2)-H(2)O was investigated at ab initio MP2 and MRSDCI levels using the aug-cc-pVTZ basis set. The vibrational levels were evaluated by numerically solving the Schrödinger equations for the nuclear motions with the ab initio potential functions using one- to three-dimensional finite-element methods. On the basis of the calculated partition functions, the equilibrium constant of the complex, K(p), was studied. The K(p) values at atmospheric temperatures of 200-300 K were found to be 1-2 orders of magnitude less than previous estimates from the harmonic oscillator approximation.
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