Effects of neon impurities on heat capacity of solid parahydrogen

Manzheliı̆, V. G.; Попов, В. А.; Chausov, G. P.; Vladimirova, L. I.

doi:10.1007/bf00655343

Cited by 15 publications

(3 citation statements)

References 6 publications

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“…37 In addition to spectroscopy, impurities have been studied through their effects on the heat capacity of solid parahydrogen. 38 The theoretical calculations which model these effects 39 are relevant to this paper.…”

Section: Introductionmentioning

confidence: 99%

High-resolution infrared spectroscopy of isotopic impurity Q1(0) transitions in solid parahydrogen

Weliky

Kerr

Byers

et al. 1996

The Journal of Chemical Physics

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High resolution electronic spectroscopy of 1aminonaphthalene: S 0 and S 1 geometries and S 1←S 0 transition moment orientationsWe have made a high-resolution infrared spectroscopic study of the Q 1 (0) ͑vϭ1←0, Jϭ0←0͒ vibrational transitions of the isotopic impurities D 2 and HD in solid parahydrogen. Each impurity has a spectrum composed of ϳ100 sharp lines spread over ϳ0.4 cm Ϫ1 . The linewidths vary, but are on the order of 10 MHz. These spectra make clear: ͑1͒ the infrared Q 1 (0) transitions of Jϭ0 isotopic impurities are induced by the quadrupolar fields of nearby impurity Jϭ1 molecules; and ͑2͒ the spectral pattern of strong Q 1 (0) lines is due to the splitting of the M -orientational levels of Jϭ1/Jϭ0 o-D 2 or Jϭ1/Jϭ0 HD nearest-neighbor ͑nn͒ impurity pairs. With the aid of several theoretical works, the strong lines in the D 2 and HD spectra can be individually and unambiguously assigned as specific quantum state Q 1 (0) transitions of nn impurity pairs containing p-D 2 /o-D 2 or o-H 2 /o-D 2 , and o-H 2 /HD, respectively. The assigned transitions of nn impurity pairs containing o-H 2 are confirmed by combination differences which agree to within 5ϫ10 Ϫ4 cm Ϫ1 , the instrumental precision. These assignments yield complete Q 1 (0) energy level diagrams for the nn impurity pairs o-H 2 /o-D 2 and o-H 2 /HD embedded in solid parahydrogen. The experimental energy level splittings are fit to a two parameter model which describes anisotropic interactions in the parahydrogen crystal. These experimental parameters appear to have significant contributions from the changes in renormalization and lattice constant around the heavier isotopic impurity. We have also assigned a few of the weaker spectral features as Q 1 (0) transitions of more distant impurity pairs, but the bulk of these transitions are yet to be assigned. They do form a distinctive pattern and are thought to be the Q 1 (0) transitions of impurity triples and larger clusters. This study is one of the few cases for which high-resolution laser spectroscopy has been successfully applied to the condensed phase and for which many of the transitions have rigorous quantum state assignments.

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Section: Introductionmentioning

confidence: 99%

High-resolution infrared spectroscopy of isotopic impurity Q1(0) transitions in solid parahydrogen

Weliky

Kerr

Byers

et al. 1996

The Journal of Chemical Physics

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“…These clusters then result in EQQ specific heat anomalies which are dependent on the temporal history of the experiment. 3'13 However, some measurements have been reported by Manzhelii et al 16 on solid H2+ Ne, and these will be discussed later.…”

Section: Introductionmentioning

confidence: 95%

Neon impurity effects in the specific heat of solid D2

1979

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Measurements have been made of the specific heat of solid deuterium with neon impurity concentrations of between 1 and 4 %. In addition, the para-D2 concentration of the samples studied has been varied between 0.9 and 6%. An excess specific heat A C was observed above approximately 1.4 K which was proportional to the Ne concentration and independent of the para-D2 concentration. AC is attributed to resonance modes involving the heavy neon atoms randomly distributed throughout the host lattice. The values of AC are qualitatively in general agreement with classical theory, with the quantitative differences due to the quantum nature of the solid.

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“…The solid Ne-H 2 (Ne-D 2 ) mixtures prepared by condensing a gas phase directly into a solid one can form nonequilibrium long-living semiquantum objects -new phases of solutions, molecular complexes Ne(H 2 ) n (Ne(D 2 ) n ) and clusters Ne(o-H 2 ), (Ne(p-D 2 )) [1][2][3][4][5][6][7]. The formation of these objects leads to new features of the physical properties of the system.…”

Section: Introductionmentioning

confidence: 99%

The effect of n-H2 impurity on the heat capacity of solid Ne

Bagatskii

Minchina

Parbuzin

2009

Low Temperature Physics

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The alloy of Ne -5.1% n-H 2 was investigated calorimetrically under equilibrium vapor pressure in an interval of 0.9-25 K. The magnitudes and the temperatures dependencies of the heat capacity C T sol ( )of the alloy at T = 11-20 K are strongly dependent on the conditions of sample preparation. The temperatures dependencies of the C T sol ( ) of the sample prepared in a calorimeter by direct condensation of a gas mixture at T » 15 K exhibit a smeared maximum near the triple point temperature of hydrogen and a phase transition at T = 17.1 K. The detected features of C T sol ( ) indicate that the preparation of the solid Ne -n-H 2 from a gas phase leads to the formation of a nonequilibrium long-living phase Ne with large H 2 concentrations and a small portion of H 2 inclusions with low Ne concentrations. The phase transition is caused by decompositions of this phase. The phase dose not recover on cooling the sample after the phase transition. It is found that the rate of the ortho-para conversion of the H 2 molecules in the solid Ne -n-H 2 solutions higher than that of solid H 2 .

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Effects of neon impurities on heat capacity of solid parahydrogen

Cited by 15 publications

References 6 publications

High-resolution infrared spectroscopy of isotopic impurity Q1(0) transitions in solid parahydrogen

High-resolution infrared spectroscopy of isotopic impurity Q1(0) transitions in solid parahydrogen

Neon impurity effects in the specific heat of solid D2

The effect of n-H2 impurity on the heat capacity of solid Ne

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