The complex kinetics of the ice VI to ice XV hydrogen ordering phase transition

Shephard, Jacob J.; Salzmann, Christoph G.

doi:10.1016/j.cplett.2015.07.064

Cited by 37 publications

(96 citation statements)

References 34 publications

(49 reference statements)

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“…That is, by enhancing the hydrogen dynamics through suitable extrinsic point defects, it is possible to unlock a transition to a hydrogen-ordered phase. Similar results were reported for other disordered ice phases, e.g., ice V or ice VI [28,29]. For all high-pressure ice phases, HCl was found to be the most efficient dopant, whereas for the low-pressure hexagonal ice, KOH was found to be most efficient [19].…”

Section: B Glass and Hydrogen-ordering Transitions In Crystalline Icessupporting

confidence: 84%

Nature of Water’s Second Glass Transition Elucidated by Doping and Isotope Substitution Experiments

et al. 2019

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Based on calorimetry and dielectric spectroscopy, the influence of dopants as well as H/D-isotope substitution on the dynamics and thermodynamics of expanded high-density amorphous ice (eHDA) is studied. We find that dopants do not significantly alter the phase behavior, the dielectric relaxation times, and the calorimetric glass transition of eHDA. These observations starkly contrast those made for crystalline ices such as ice I h , ice V, ice VI, and ice XII, where suitable dopants enhance the dielectric dynamics by several orders of magnitude and can trigger hydrogen order-disorder transitions, then taking place below the orientational glass transition temperature of undoped samples. This conspicuous contrast to the behavior of crystalline ices strongly argues against point-defect dynamics in amorphous ices and against a previously suggested "crystallinelike" nature of the amorphous ices. Furthermore, H/D substitution also does not affect the calorimetric glass transition in eHDA much, whereas for crystalline ices, the heat capacity increase at the glass transition is roughly halved. In addition, the H/D-isotope shift of the glass transition onset is much larger for crystalline ices than it is for amorphous ices. This observation favors the notion of eHDA's glass transition as a glass-to-liquid transition and is evidence against a mere molecular-reorientation unfreezing at water's second glass transition. Comparing the isotope effect on activation energies for dielectric relaxation with ice V suggests that in amorphous ice water molecules move translationally above T g. Thus, the present work strongly supports that above this glass transition, water does indeed exist in its contested high-density liquid state.

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Section: B Glass and Hydrogen-ordering Transitions In Crystalline Icessupporting

confidence: 84%

Nature of Water’s Second Glass Transition Elucidated by Doping and Isotope Substitution Experiments

et al. 2019

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“…Polymorphism in H 2 O-ices is intimately linked with hydrogen and oxygen atom order. [1][2][3][4][5][6][7] An ice polymorph may transform from an H-disordered high-temperature variant to its H-ordered low-temperature proxy, while the network of O-atoms is barely affected. 8 Ice VI is one of the high-pressure, H-disordered polymorphs, which is stable at 0.6-2.2 GPa.…”

Section: Introductionmentioning

confidence: 99%

“…9 Ice VI may transform to its H-ordered pendant ice XV, e.g., upon cooling at 1.0 GPa below 129 K. 10 In pure water samples this transformation is so slow that it usually does not occur due to lack of time. 5,11 Under such conditions ice VI is kinetically stable and would transform to ice XV over an infinite period of time. This state of ice VI is then called a ''glassy state''.…”

Section: Introductionmentioning

confidence: 99%

Distinguishing ice β-XV from deep glassy ice VI: Raman spectroscopy

Thoeny

Gasser

Loerting

2019

Phys. Chem. Chem. Phys.

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“…46 The acid dopant introduces mobile point defects which speed up molecular reorientation processes and therefore facilitate hydrogen ordering. 46,[49][50][51][52] The ice V → ice XIII phase transition takes place upon isobaric cooling of ice V from its region of stability, but it can also be observed in a reversible fashion upon heating/cooling at ambient pressure with a phase transition temperature of 112 K. 50 Upon hydrogen-ordering, the space group changes from A2/a to P2 1 /a, which is why also the oxygen structure changes slightly. 46 This leads to 7 crystallographically distinct water molecules and 14 different types of hydrogen bonds of equal multiplicity.…”

Section: A Background: Ices Ih II V and Xiiimentioning

confidence: 99%

2D IR spectroscopy of high-pressure phases of ice

Tran

Cunha

Shephard

et al. 2017

The Journal of Chemical Physics

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We present experimental and simulated 2D IR spectra of some high-pressure forms of isotope-pure D 2 O ice and compare the results to those of ice Ih published previously [F. Perakis and P. Hamm, Phys. Chem. Chem. Phys. 14, 6250 (2012); L. Shi et al., ibid. 18, 3772 (2016)]. Ice II, ice V, and ice XIII have been chosen for this study, since this selection covers many aspects of the polymorphism of ice. That is, ice II is a hydrogen-ordered phase of ice, in contrast to ice Ih, while ice V and ice XIII are a hydrogen-disordered/ordered couple that shares essentially the same oxygen structure and hydrogenbonded network. For the transmission 2D IR spectroscopy, a novel method had to be developed for the preparation of ultrathin films (1-2 µm) of high-pressure ices with good optical quality. We also simulated 2D IR spectra based on molecular dynamics simulations connected to a vibrational exciton picture. These simulations agree with the experimental results in a semi-quantitative manner for ice II, while the same approach failed for ice V and ice XIII. From the perspective of 2D IR spectroscopy, ice II appears to be more inhomogeneously broadened than ice Ih, despite its hydrogen-order, which we attribute to the fact that ice II is structurally more complex with four distinguishable hydrogen bonds that mix due to exciton coupling. Ice V and ice XIII, on the other hand, behave as expected with the hydrogen-disordered case (ice V) being more inhomogenously broadened. Furthermore, in all hydrogen-ordered forms (ice II and ice XIII), cross peaks could be identified in the anisotropic 2D IR spectrum, whose signs reveal the relative direction of the corresponding excitonic states. Published by AIP Publishing. https://doi

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The complex kinetics of the ice VI to ice XV hydrogen ordering phase transition

Cited by 37 publications

References 34 publications

Nature of Water’s Second Glass Transition Elucidated by Doping and Isotope Substitution Experiments

Nature of Water’s Second Glass Transition Elucidated by Doping and Isotope Substitution Experiments

Distinguishing ice β-XV from deep glassy ice VI: Raman spectroscopy

2D IR spectroscopy of high-pressure phases of ice

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