Cryogenic microjet for exploration of superfluidity in highly supercooled molecular hydrogen

Grisenti, R. E.; Fraga, R. A. Costa; Petridis, N.; Dørner, R.; Deppe, J.

doi:10.1209/epl/i2005-10433-3

Cited by 29 publications

(28 citation statements)

References 21 publications

(41 reference statements)

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“…2,11 On the other hand, diffusion Monte Carlo ͑DMC͒ T = 0 calculations indicate that N = 13 and possibly 19 and 33 are magic and energetically more stable than the neighboring sizes, consistent with the clusters being solidlike. 10,13,17 PIMC calculations at 0.5Յ T Յ 4.5 K indicate also that N = 19,23,26,29,32, and 37 clusters are magic in agreement with icosahedral magic numbers expected for solid clusters. 14,16 Other PIMC calculations suggest that below about 0.75-0.25 K the quantum delocalization is greatly enhanced 19,20 favoring superfluidity.…”

Section: Introductionsupporting

confidence: 65%

Why are para-hydrogen clusters superfluid? A quantum theorem of corresponding states study

Sevryuk

Toennies

Ceperley

2010

The Journal of Chemical Physics

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The quantum theorem of corresponding states is applied to N=13 and N=26 cold quantum fluid clusters to establish where para-hydrogen clusters lie in relation to more and less quantum delocalized systems. Path integral Monte Carlo calculations of the energies, densities, radial and pair distributions, and superfluid fractions are reported at T=0.5 K for a Lennard-Jones (LJ) (12,6) potential using six different de Boer parameters including the accepted value for hydrogen. The results indicate that the hydrogen clusters are on the borderline to being a nonsuperfluid solid but that the molecules are sufficiently delocalized to be superfluid. A general phase diagram for the total and kinetic energies of LJ (12,6) clusters encompassing all sizes from N=2 to N=infinity and for the entire range of de Boer parameters is presented. Finally the limiting de Boer parameters for quantum delocalization induced unbinding ("quantum unbinding") are estimated and the new results are found to agree with previous calculations for the bulk and smaller clusters.

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Section: Introductionsupporting

confidence: 65%

Why are para-hydrogen clusters superfluid? A quantum theorem of corresponding states study

Sevryuk

Toennies

Ceperley

2010

The Journal of Chemical Physics

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“…However, recent experiments have indicated that, even at T ∼ 9 K, the rate of crystal growth is so high that the liquid phase freezes quickly into a metastable polymorph crystal. 10 Even though several supercooling techniques have been proposed to create a metastable liquid phase in bulk p-H 2 , [11][12][13] none of them has proven so far to be successful and no direct evidence of superfluidity has been detected. However, there are evidences of superfluidity in several spectroscopic studies of small doped p-H 2 clusters.…”

Section: Introductionmentioning

confidence: 99%

“…Other attempts of producing liquid p-H 2 well below T f (T = 1.3 K) are based on the generation of continuous hydrogen filaments of macroscopic dimensions. 13 The search for a superfluid p-H 2 phase has been intense also from the theoretical point of view. The rather simple radial form of the p-H 2 -p-H 2 interaction and the microscopic accuracy achieved by quantum Monte Carlo methods have stimulated a long-standing effort for devising possible scenarios where supercooled p-H 2 could be studied.…”

Section: Introductionmentioning

confidence: 99%

Superfluidity of metastable glassy bulkpara-hydrogen at low temperature

2012

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Molecular para-hydrogen (p-H 2 ) has been proposed theoretically as a possible candidate for superfluidity, but the eventual superfluid transition is hindered by its crystallization. In this work, we study a metastable noncrystalline phase of bulk p-H 2 by means of the path integral Monte Carlo method in order to investigate at which temperature this system can support superfluidity. By choosing accurately the initial configuration and using a noncommensurate simulation box, we have been able to frustrate the formation of the crystal in the simulated system and to calculate the temperature dependence of the one-body density matrix and of the superfluid fraction. We observe a transition to a superfluid phase at temperatures around 1 K. The limit of zero temperature is also studied using the diffusion Monte Carlo method. Results for the energy, condensate fraction, and structure of the metastable liquid phase at T = 0 are reported and compared with the ones obtained for the stable solid phase.

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“…However, hydrogen molecules have van der Waals interactions, which are 12 times stronger than those between helium atoms and, in bulk, hydrogen solidifies at 13.8 K. The -temperature for parahydrogen has been estimated from the Bose-Einstein condensation temperature to be ϳ6 K. 10 All other forms of the hydrogen molecule ͑ortho-H 2 , para-D 2 , and ortho-D 2 ͒ are expected to have the transition occur at lower temperatures because of the degeneracy of their lowest energy level. 10 Many experiments have been made to supercool bulk hydrogen to produce a superfluid, [10][11][12][13][14] but all attempts have been unsuccessful. Gas-phase studies, where solidification may not be an issue, could potentially demonstrate the onset of superfluidity in hydrogen clusters.…”

Section: Introductionmentioning

confidence: 99%

“…measured of clusters containing OCS, O13 CS, and OC 34 S, as well as O 13 C 34 S for the ͑o-H 2 ͒ 2 -OCS cluster. The signal intensity of the clusters was sufficient to observe the J K a K c =1 01 −0 00 transition of ͑p-H 2 ͒ 2 -OCS with 10 averaging cycles.…”

mentioning

confidence: 99%

Rotational spectroscopic study of carbonyl sulfide solvated with hydrogen molecules

Michaud

Jäger

2008

The Journal of Chemical Physics

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Rotational spectra of small-sized (H(2))(N)-OCS clusters with N = 2-7 were measured using a pulsed-jet Fourier transform microwave spectrometer. These include spectra of pure (para-H(2))(N)-OCS clusters, pure (ortho-H(2))(N)-OCS clusters, and mixed ortho-H(2) and para-H(2) containing clusters. The rotational lines of ortho-H(2) molecules containing clusters show proton spin-proton spin hyperfine structure, and the pattern evolves as the number of ortho-H(2) molecules in the cluster increases. Various isotopologues of the clusters were investigated, including those with O(13)CS, OC(33)S, OC(34)S, and O(13)C(34)S. Nuclear quadrupole hyperfine structures of rotational transitions were observed for (33)S (nuclear spin quantum number I = 3/2) containing isotopologues. The (33)S nuclear quadrupole coupling constants are compared to the corresponding constant of the OCS monomer and those of the He(N)-OCS clusters. The assignment of the number of solvating hydrogen molecules N is supported by the analyses of the proton spin-proton spin hyperfine structures of the mixed clusters, the dependence of line intensities on sample conditions (pressure and concentrations), and the agreement of the (para-H(2))(N)-OCS and (ortho-H(2))(N)-OCS rotational constants with those from a previous infrared study [J. Tang and A. R. W. McKellar, J. Chem. Phys. 121, 3087 (2004)].

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Cryogenic microjet for exploration of superfluidity in highly supercooled molecular hydrogen

Cited by 29 publications

References 21 publications

Why are para-hydrogen clusters superfluid? A quantum theorem of corresponding states study

Why are para-hydrogen clusters superfluid? A quantum theorem of corresponding states study

Superfluidity of metastable glassy bulkpara-hydrogen at low temperature

Rotational spectroscopic study of carbonyl sulfide solvated with hydrogen molecules

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