Solidification and melting of gallium and mercury in porous glasses as studied by NMR and acoustic techniques

Michel, D.; Borisov, B. F.; Charnaya, E. V.; Hoffmann, Wolf-Dieter; Plotnikov, P. G.; Kumzerov, Yu. A.

doi:10.1016/s0965-9773(99)00172-5

Cited by 13 publications

(7 citation statements)

References 4 publications

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“…The freezing and melting of mercury in Vycor (d = 7 nm) was studied by neutron diffraction, calorimetry, NMR and acoustical techniques [118][119][120]. As in the case of many previously mentioned wetting simple fluids, a depression of the freezing and melting points was found with this non-wetting system.…”

Section: Metalsmentioning

confidence: 92%

Confinement effects on freezing and melting

Christenson¹

2001

J. Phys.: Condens. Matter

581

594

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A review of experimental work on freezing and melting in confinement is presented. A range of systems, from metal oxide gels to porous glasses to novel nanoporous materials, is discussed. Features such as melting-point depression, hysteresis between freezing and melting, modifications to bulk solid structure and solid-solid transitions are reviewed for substances such as helium, organic fluids, water and metals. Recent work with well characterized assemblies of cylindrical pores like MCM-41 and graphitic microfibres with slit pores has suggested that the macroscopic picture of melting and freezing breaks down in pores of molecular dimensions. Applications of the surface force apparatus to the study of freezing and melting phenomena in confinement are discussed in some detail. This instrument is unique in allowing the study of conditions in a single pore, without the complications of pore blockage and connectivity effects. The results have confirmed the classical picture of melting-point depression in larger pores, and allowed the direct observation of capillary condensation of solid from vapour. Other results include the measurement of solvation forces across apparently fluid films below the bulk melting point and a solid-like response to shear of films above the bulk melting point. These somewhat contradictory findings highlight the difficulty of using bulk concepts to define the phase state of a substance confined to nanoscale pores.

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Section: Metalsmentioning

confidence: 92%

Confinement effects on freezing and melting

Christenson¹

2001

J. Phys.: Condens. Matter

581

594

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“…The rate of transverse relaxation in the samples under study can be estimated from the width of NMR lines. Note, however, that the experimental line shapes might also be influenced by the inhomogeneity of the Knight shift due to pore size distribution [26]. The relationship for the time decay of transverse magnetization M Ќ due to quadrupolar spin relaxation in liquids can also be found in [23] and simplified in the same manner as (1).…”

mentioning

confidence: 99%

“…The time T 1m of magnetic relaxation caused by coupling with conduction electrons is related to the Knight shift by the Korringa relation: T 1m TK 2 s const͑͞g n K͒, where T is the temperature, K s is the Knight shift, and K is the correction factor. Since the Knight shift in liquid gallium is influenced by confinement but very slightly [26], the time T 1m for confined gallium can be assumed for estimates to keep its bulk value. The magnetic and quadrupolar contributions to spin-lattice relaxation in bulk liquid gallium were separated [20,21] for both gallium isotopes using their gyromagnetic ratios and quadrupole moments.…”

mentioning

confidence: 99%

Spin-Lattice Relaxation Enhancement in Liquid Gallium Confined within Nanoporous Matrices

et al. 2002

Self Cite

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Nuclear spin relaxation for liquid gallium embedded into nanoporous matrices was found to accelerate remarkably compared to the bulk melt. NMR measurements on two gallium isotopes showed that the dominant mechanism of relaxation was changed from magnetic to quadrupolar and the relation rate depended on the Larmor frequency. The correlation time of electric field gradient fluctuations was estimated using data for quadrupolar relaxation contribution and was found to increase drastically compared to bulk, which corresponded to slowing down mobility in confined liquid gallium.

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“…In relation to the observed size effect, it is worth mentioning various previous investigations on the confinement of Hg in nanometric configurations. Among them, one should mention the experimental observations in 2003 of Kasperovich et al 14 , in 1998 of Borisov et al 15 , 16 and in 1986 of Kumzerov et al 17 , 18 . More precisely, Kasperovich et al 14 have conducted NMR studies on Hg embedded in restricted geometry of nano-porous carbon and nano-porous silica gel with ~ 4.7 and ~ 3.9 nm in radius respectively.…”

Section: Experiments Experimental Results and Discussionmentioning

confidence: 98%

Mercury goes Solid at room temperature at nanoscale and a potential Hg waste storage

Kana

Morad

Akbari

et al. 2022

Sci Rep

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While room temperature bulk mercury is liquid, it is solid in its nano-configuration (Ønano-Hg ≤ 2.5 nm). Conjugating the nano-scale size effect and the Laplace driven surface excess pressure, Hg nanoparticles of Ønano-Hg ≤ 2.4 nm embedded in a 2-D turbostratic Boron Nitride (BN) host matrix exhibited a net crystallization at room temperature via the experimentally observed (101) and (003) diffraction Bragg peaks of the solid Hg rhombohedral α-phase. The observed crystallization is correlated to a surface atomic ordering of 7 to 8 reticular atomic plans of the rhombohedral α-phase. Such a novelty of size effect on phase transition phenomena in Hg is conjugated to a potential Hg waste storage technology. Considering the vapor pressure of bulk Hg, Room Temperature (RT) Solid nano-Hg confinement could represent a potential green approach of Hg waste storage derived from modern halogen efficient light technology.

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Solidification and melting of gallium and mercury in porous glasses as studied by NMR and acoustic techniques

Cited by 13 publications

References 4 publications

Confinement effects on freezing and melting

Confinement effects on freezing and melting

Spin-Lattice Relaxation Enhancement in Liquid Gallium Confined within Nanoporous Matrices

Mercury goes Solid at room temperature at nanoscale and a potential Hg waste storage

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