Potential generation and path‐integral <scp>M</scp>onte <scp>C</scp>arlo in study of microscopic superfluidity

Zeng, Tao; Li, Hui; Roy, Pierre‐Nicholas

doi:10.1002/qua.24815

Cited by 4 publications

(1 citation statement)

References 90 publications

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“…The study of hydrogen clusters has been the subject of much research in both theory and experiment, a key reason being that superfluid properties of parahydrogen have been observed at low temperatures. , In 1972, Ginzburg and Sobyanin started the discussion, suggesting that pH 2 may be a superfluid and proposed several ways to observe it. The next major theoretical breakthrough was in 1991, as Sindzingre et al calculated the superfluid fractions of pH 2 clusters using the Path Integral Monte Carlo (PIMC) method and observed that, below 2 K, (pH 2 ) 13 and (pH 2 ) 18 were superfluid, but (pH 2 ) 33 remained nonsuperfluid.…”

Section: Introductionmentioning

confidence: 99%

Raman Vibrational Shifts of Small Clusters of Hydrogen Isotopologues

et al. 2015

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Raman vibrational shifts of small parahydrogen (pH2), orthodeuterium (oD2), and paratritium (pT2) clusters with respect to the free molecules are calculated by combining a first order perturbation theory approach with Langevin equation Path Integral Ground State (LePIGS) simulations [ J. Phys. Chem. A 2013 , 117 , 7461 ]. Our theoretical predictions are compared to existing cryogenic free jet expansion results for pure (pH2)N clusters [ Phys. Rev. Lett. 2004 , 92 , 223401 ] and to new measurements for (oD2)N clusters reported here. This method has been successfully used before to predict the Raman vibrational shifts of (pH2)N clusters [ J. Chem. Phys. 2014 , 141 , 014310 ]. The 6-D interaction potential of Hinde [ J. Chem. Phys. 2008 , 128 , 154308 ] is reduced to 1-D using the Adiabatic Hindered Rotor approximation to yield effective pair potentials for both molecules being in the ground vibrational state, and for one of them carrying one quantum of vibrational excitation. These reduced 1-D potentials are fitted to a Morse Long Range analytic form for later convenience. Good agreement between experiment and theory is found for the smaller clusters, but significant deviations remain for the larger ones.

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Section: Introductionmentioning

confidence: 99%

Raman Vibrational Shifts of Small Clusters of Hydrogen Isotopologues

et al. 2015

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Note: On the inclusion of a diagonal Born-Oppenheimer correction in the reduced dimensional treatment of the H2O–para-H2 complex

Scribano

Fauré

2017

The Journal of Chemical Physics

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Explicit correlation treatment of the six-dimensional potential energy surface and predicted infrared spectra for OCS–H2

Liu

Zhai

2017

The Journal of Chemical Physics

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An effective six-dimensional ab initio potential energy surface (PES) for H-OCS which explicitly includes the intramolecular stretch normal modes of carbonyl sulfide (OCS) is presented. The electronic structure computations are carried out using the explicitly correlated coupled cluster [CCSD(T)-F12] method with the augmented correlation-consistent aug-cc-pVTZ basis set, and the accuracy is critically tested by performing a series of benchmark calculations. Analytic four-dimensional PESs are obtained by least-squares fitting vibrationally averaged interaction energies to the Morse/long-range potential model. These fits to 13 485 points have a root-mean-square deviation (RMSD) of 0.16 cm. The combined radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm were employed to evaluate the rovibrational energy levels for five isotopic species of the OCS-hydrogen complexes. The predicted transition frequencies and intensities based on the resulting vibrationally averaged PESs are in good agreement with the available experimental values, whose RMSDs are smaller than 0.004 cm for five different species of OCS-hydrogen complexes. The calculated infrared band origin shifts for all five species of OCS-hydrogen complexes are only 0.03 cm smaller than the corresponding experimental values. These validate the high quality of our PESs which can be used for modeling OCS doped in hydrogen clusters to further study quantum solution and microscopic superfluidity. In addition, the analytic coordinate transformation functions between isotopologues are also derived due to the center of mass shifting of different isotope substitutes.

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Potential generation and path‐integral Monte Carlo in study of microscopic superfluidity

Cited by 4 publications

References 90 publications

Raman Vibrational Shifts of Small Clusters of Hydrogen Isotopologues

Raman Vibrational Shifts of Small Clusters of Hydrogen Isotopologues

Note: On the inclusion of a diagonal Born-Oppenheimer correction in the reduced dimensional treatment of the H2O–para-H2 complex

Explicit correlation treatment of the six-dimensional potential energy surface and predicted infrared spectra for OCS–H2

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