Nuclear spin conversion of methane in solid parahydrogen

Spectroscopic studies of recently synthesized endofullerenes, in which H 2 , H 2 O and other atoms and small molecules are trapped in cages of carbon atoms, have shown that although the trapped molecules interact relatively weakly with the internal environment they are nevertheless susceptible to appropriately applied external perturbations. These properties have been exploited to isolate and study samples of H 2 in C 60 and other fullerenes that are highly enriched in the para spin isomer. Several strategies for spin-isomer enrichment, potential extensions to other endofullerenes and possible applications of these materials are discussed.

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“…However, nuclear spin conversion in CH 4 , both uncatalysed [59] and catalysed by O 2 [60], has been studied in the solid at low temperatures.…”

Section: And Chmentioning

confidence: 99%

Nuclear spin isomers of guest molecules in H ₂ @C ₆₀ , H ₂ O@C ₆₀ and other endofullerenes

Chen

Frunzi

et al. 2013

Phil. Trans. R. Soc. A.

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“…Study of these processes has been carried out either directly using structural methods [6,7] and the method of nuclear magnetic resonance [8][9][10], or indirectly, by examining the impact of conversion processes on the macroscopic characteristics of solid methane. This most clearly affects the vibrational spectra of methane in the range of translational and librational vibrations [11,12], as well as the thermophysical properties of methane, such as heat capacity [13,14], thermal conductivity [15], and density [16,17].…”

Section: Introductionmentioning

confidence: 99%

Refractive indices and density of cryovacuum-deposited thin films of methane in the vicinity of the α-β-transition temperature

Drobyshev¹,

Aldiyarov²,

Sokolov³

et al. 2017

Low Temperature Physics

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Experimental studies of the effect of methane condensation temperature on the value of the refractive index and density of the resulting thin films are reported. The main unit of the installation is a high-vacuum chamber, which routinely operates at 10 -8 -10 -6 Torr. Measurements using a two-beam He-Ne laser interferometer in the vicinity of the methane phase transition temperature T = 20.4 K in the range of 14-32 K were carried out. It has been shown that in the vicinity of T = 20 K the temperature dependence of the refractive index undergoes an abrupt decrease with decreasing temperature. It is assumed that this gap is the result of the phase transition from the orientational disordered phase (α-phase) to the partially ordered phase (β-phase) of solid methane. The calculations of the polarizability of the methane molecules in the solid phase at two values of the deposition temperature T = 16 K and T = 30 K were performed using the Lorentz-Lorenz equation.

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“…More complex forms of spin isomerism exist for the symmetrical polyatomic molecules NH 3 and CH 4 [59,60].…”

Section: (I) Closed Fullerenesmentioning

confidence: 99%

Spectroscopy of light-molecule endofullerenes

Levitt

2013

Phil. Trans. R. Soc. A.

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Molecular endofullerenes are supramolecular systems consisting of fullerene cages encapsulating small molecules. Although most early examples consist of encapsulated metal clusters, recently developed synthetic routes have provided endofullerenes with non-metallic guest molecules in high purity and macroscopic quantities. The encapsulated light molecule behaves as a confined quantum rotor, displaying rotational quantization as well as translational quantization, and a rich coupling between the translational and rotational degrees of freedom. Furthermore, many encapsulated molecules display spin isomerism. Spectroscopies such as inelastic neutron scattering, nuclear magnetic resonance and infrared spectroscopy may be used to obtain information on the quantized energy level structure and spin isomerism of the guest molecules. It is also possible to study the influence of the guest molecules on the cages, and to explore the communication between the guest molecules and the molecular environment outside the cage.

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Nuclear spin conversion of methane in solid parahydrogen

Cited by 48 publications

References 70 publications

Nuclear spin isomers of guest molecules in H ₂ @C ₆₀ , H ₂ O@C ₆₀ and other endofullerenes

Nuclear spin isomers of guest molecules in H ₂ @C ₆₀ , H ₂ O@C ₆₀ and other endofullerenes

Refractive indices and density of cryovacuum-deposited thin films of methane in the vicinity of the α-β-transition temperature

Spectroscopy of light-molecule endofullerenes

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Nuclear spin conversion of methane in solid parahydrogen

Cited by 48 publications

References 70 publications

Nuclear spin isomers of guest molecules in H 2 @C 60 , H 2 O@C 60 and other endofullerenes

Nuclear spin isomers of guest molecules in H 2 @C 60 , H 2 O@C 60 and other endofullerenes

Refractive indices and density of cryovacuum-deposited thin films of methane in the vicinity of the α-β-transition temperature

Spectroscopy of light-molecule endofullerenes

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Product

Resources

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Nuclear spin isomers of guest molecules in H ₂ @C ₆₀ , H ₂ O@C ₆₀ and other endofullerenes

Nuclear spin isomers of guest molecules in H ₂ @C ₆₀ , H ₂ O@C ₆₀ and other endofullerenes