The Journal of Chemical Physics · 2014 · 18 citations · 34 references
Natural SciencesChemistryPhysicsComputational ChemistryPhysical ChemistryTheoretical ChemistryAb Initio MethodsCluster ChemistryDensity Functional TheoryMolecular Orbital TheoryPotential Energy SurfacesRaman SpectroscopyAb Initio Potential Energy SurfacesEffective Pair PotentialsFirst-principles ModelingMolecular Perturbation TheoryPair PotentialsRadial Distribution FunctionsRaman Shift AnalysisRaman Spectra
We report a first-principles prediction of the Raman shifts of parahydrogen (pH2) clusters of sizes N = 4-19 and 33, based on path integral ground-state simulations with an ab initio potential energy surface. The Raman shifts are calculated, using perturbation theory, as the average of the difference-potential energy surface between the potential energy surfaces for vibrationally excited and ground-state parahydrogen monomers. The radial distribution of the clusters is used as a weight function in this average. Very good overall agreement with experiment [G. Tejeda, J. M. Fernández, S. Montero, D. Blume, and J. P. Toennies, Phys. Rev. Lett. 92, 223401 (2004)] is achieved for p(H2)(2-8,13,33). A number of different pair potentials are employed for the calculation of the radial distribution functions. We find that the Raman shifts are sensitive to slight variations in the radial distribution functions.
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Evidence for Superfluidity in Para-Hydrogen Clusters Inside Helium-4 Droplets at 0.15 Kelvin
Slava Grebenev, Boris G. Sartakov, J. P. Toennies et al. · Science · 2000 · 226 citations