The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm<sup>−1</sup>

Bertie, John E.; Othen, D. A.

doi:10.1139/v73-174

Cited by 27 publications

(10 citation statements)

References 13 publications

(20 reference statements)

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“…Other infrared absorption bands characteristic of enclathrated EO, such as the well-studied C−O stretch bands near 1270 cm -1 , , also mark the complete conversion to nanocrystals of the clathrate. Further, band intensities, of near-monolayer quantities of CF 4 adsorbed on the new icy phase, have shown that the clathrate nanocrystals retain a size similar to that of the original ice nanocrystals (i.e., ∼50 nm in diameter for particles annealed at 140 K).…”

Section: Resultsmentioning

confidence: 99%

“…Simultaneously, the sharper band of the OH stretch mode of isolated HDO evolves to the broad band characteristic of the clathrate hydrate (Figure 3B), and the C-H stretch bands for EO in the large cage of the type I clathrate emerge. 31 From the molecular mechanism for formation of the monohydrate of ammonia and the simulation results of Tanaka for clathrate rearrangement, 30 it is reasonable to assume that the formation of the clathrate hydrate occurs by a molecular/defect mechanism that involves the breaking of old H bonds and the formation of new ones.…”

Section: Resultsmentioning

confidence: 99%

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Ice Surface Reactions with Acids and Bases

et al. 1997

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Previous Fourier-transform infrared spectroscopic studies of adsorbates on the surface of ice nanocrystals have considered two categories of molecular adsorbates: (a) weak adsorbates that desorb rapidly into a vacuum at T < 100 K and that influence the vibrational modes of only the surface molecules of ice and (b) adsorbates that form significant H bonds to the unsaturated surface groups resist desorption at temperatures below ∼120 K and, without penetrating the ice, alter the subsurface ice spectrum. Here, we consider a third category of adsorbates which is characterized by molecules that form strong H bonds with the ice surface, penetrate the ice, and form hydrates. It is shown that above some minimum temperature of adsorption strong acids and Lewis base molecules, including ethers and amines, penetrate the ice and ultimately form known crystalline hydrates of the adsorbate. Results are reported for HCl, ethylene oxide, and ammonia as representative of these three subclasses of penetrating/reacting adsorbates. Ethylene oxide is shown to convert nanocrystals of ice to nanocrystals of the type I clathrate hydrate at 130 K. Similarly, nanocrystals of ice, exposed to NH 3 at 120 K, convert slowly to nanocrystals of the monohydrate of ammonia by a molecular reaction mechanism. By contrast, HCl, following adsorption in the 60-125 K range, converts ice nanocrystals to the amorphous ionic monohydrate which crystallizes upon warming above 135 K. However, below 50 K, adsorbed HCl exists primarily as the molecular adsorbate with a behavior similar to that observed for adsorption on amorphous ice. Disorder associated with the surface reconstruction of bare ice and the presence of strained H bonds between water molecules of the relaxed surface are likely critical factors in the interaction/reaction with adsorbates, such as atmospherically important HCl. However, the ability of strong proton donor/acceptor molecules to break and replace stable H bonds to water molecules is considered a prerequisite for the observed complete conversion of ice nanocrystals to hydrates at cryogenic temperatures.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ice Surface Reactions with Acids and Bases

et al. 1997

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“…The vibrational spectrum of a host lattice of a CH resembles that of ice I [Bertie and Othen, 1972]. However, •e CHs have subsets of oxygen-oxygen near-neighbor distances of different lengths, ranging from about 2.74 to 2.82 angstroms [Davidson, 1972] and ASW, often shifted somewhat to higher frequencies versus ice I.…”

Section: Spectroscopy Of C!athrate Hydratesmentioning

confidence: 99%

“…The host bandwidths also reflect dynamical intermolecular coupling that is reduced by isotopic dilution [Devlin, 1990]. The spectra of guest molecules in CHs are generally distinctive but reflect only minor perturbations from the CH cage environments [Bertie and Othen, 1972]. However, at least two unique characteristics have been noted.…”

Section: Spectroscopy Of C!athrate Hydratesmentioning

confidence: 99%

Structure, spectra, and mobility of low‐pressure ices: Ice I, amorphous solid water, and clathrate hydrates at T < 150 K

Devlin¹

2001

J. Geophys. Res.

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Abstract. Recent advances in the study of low-pressure water ices, including clathrate hydrates, are examined, highlighting aspects of modern science possibly related to the behavior of water ices in extraterrestrial environments. An effort has been made to identify properties of ice that are likely to be important in the conditions that exist in such environments and to review advances in understanding these properties. The basic science of crystalline ice I is relatively mature, but attention is given to concepts, such as point defects, which continue to evolve and which relate in an important manner to the low-temperature behavior of ice ! as well as of amorphous ice and the clathrate hydrates. A concept of amorphous and microporous amorphous ice, developed in the early 1980s, is presented, but more recent characterizations are emphasized. Similarly, fundamental properties of clathrate hydrates are summarized and used in discussions of more recently appreciated characteristics that may be important in space science. Particular emphasis is placed on the formation, infrared spectroscopy, and behavior of clathrate hydrates in vacuo at temperatures below 150 K. The review closes with a section on the properties of ice nanoparticles, which have only recently emerged as a subject of molecular science. Modern experimental and theoretical studies of ice particles have focused on the infrared spectra and structure of the ice surface, and the interaction of the surface with molecular adsorbates. Since, with the exception of highenergy radiation, ice normally interacts with its environment through surface processes, such research may enlighten future studies.

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“…The EO hydrate was discussed and characterized in detail using X-ray diffraction by von Stackelberg and Meuthen . The single-crystal X-ray crystal structure of this hydrate was determined by McMullan and Jeffreyand later refined by Udachin et al The IR spectrum of EO hydrate was measured by Bertie and Othen , and the dielectric relaxation by Hawkins and Davidson, who were also the first to prepare the sI trimethylene oxide (TMO) clathrate hydrate. The powder neutron diffraction of the TMO clathrate hydrate was determined by Rondinone et al and the single crystal X-ray diffraction of this phase with accurate guest positions was determined by Udachin et al Gough et al, and Udachin et al detected an ordering transition where the TMO guest molecules align parallel in each row of T cages in the sI clathrate hydrate phase.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Study of Guest–Host Hydrogen Bonding in Ethylene Oxide, Trimethylene Oxide, and Formaldehyde Structure I Clathrate Hydrates

2017

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Molecular dynamics simulations are used to study the guest−host hydrogen bonding and guest dynamics in the clathrate hydrate phases of trimethylene oxide (TMO), ethylene oxide (EO), and formaldehyde (FA) as polar guests. Two water models, the SPC/E and TIP4P/ice, were used in the simulations. Binary hydrates are constructed with these guests in the large 14-sided cages and methane placed in the small 12-sided cages of the structure sI clathrate hydrates. The results of these simulations are compared with the nonpolar guests with analogous structures, cyclobutane (CB), cyclopropane (CP), and ethane, respectively, for TMO, EO, and FA. These simulations show that oxygen atoms of the cyclic ethers and carbonyl oxygen of formaldehyde form hydrogen bonds to differing degrees with cage water hydrogen atoms. The TMO size is larger than that of the EO and FA molecules and the closer proximity of the atoms of this large guest to the cage water molecule enhances the probability of guest−host hydrogen bonding in the TMO clathrate. The TMO oxygen atom is tethered by a lattice water hydrogen atom by hydrogen bonding for longer times, which reduces the range of translational and rotational motions of the TMO guests in the cages compared to EO and FA. The effect of guest−host hydrogen bond formation is the insertion of Bjerrum L-defects in the clathrate water lattice. We consider guest dynamic properties such as velocity autocorrelation function (VACF) and orientational autocorrelation function (OACF) of the different guests in these hydrate phases and compare the hydrogen bonding and non-hydrogen bonding analogues. We discuss some other potential experimentally observable effects of the guest−host hydrogen bonding on the guest and water dynamics in the corresponding clathrate hydrates.

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The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm⁻¹

Cited by 27 publications

References 13 publications

Ice Surface Reactions with Acids and Bases

Ice Surface Reactions with Acids and Bases

Structure, spectra, and mobility of low‐pressure ices: Ice I, amorphous solid water, and clathrate hydrates at T < 150 K

Molecular Dynamics Study of Guest–Host Hydrogen Bonding in Ethylene Oxide, Trimethylene Oxide, and Formaldehyde Structure I Clathrate Hydrates

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The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm−1

Cited by 27 publications

References 13 publications

Ice Surface Reactions with Acids and Bases

Ice Surface Reactions with Acids and Bases

Structure, spectra, and mobility of low‐pressure ices: Ice I, amorphous solid water, and clathrate hydrates at T < 150 K

Molecular Dynamics Study of Guest–Host Hydrogen Bonding in Ethylene Oxide, Trimethylene Oxide, and Formaldehyde Structure I Clathrate Hydrates

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The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm⁻¹