The thermodynamic stability of clathrate hydrate is calculated under a wide range of temperature and pressure conditions applicable to solar system problems, using a statistical mechanical theory developed by van der Waals and Platteeuw (1959) and existing experimental data on properties of clathrate hydrates and their components. At low pressure, dissociation pressures and partition functions ...

A new predictive computational method for classifying clathrate hydrate promoter molecules is presented, based on the interaction energies between potential promoters and the water networks of sII and sH clathrates. The motivation for this work is identifying promoters for storing hydrogen compactly in clathrate hydrates. As a first step towards achieving this goal, we have developed a general ...

Vibrational frequency shifts of H2 in clathrate hydrates are important to understand the properties and elucidate details of the clathrate structure. Experimental spectra of H2 in clathrate hydrates have been measured for different clathrate compositions, temperatures, and pressures. In order to establish reliable relationships between the clathrate structure, dynamics, and observed frequencies...

To investigate the preservation of CO2 clathrate hydrate in the presence of sugar for the novel frozen dessert, mass fractions of CO2 clathrate hydrate in CO2 clathrate hydrate samples coexisting with trehalose were intermittently measured. The samples were prepared from trehalose aqueous solution with trehalose mass fractions of 0.05 and 0.10 at 3.0 MPa and 276.2 K. The samples having particle...

A high-pressure investigation of the Xe*H(2)O chemical system was conducted by using diamond-anvil cell techniques combined with in situ Raman spectroscopy, synchrotron x-ray diffraction, and laser heating. Structure I xenon clathrate was observed to be stable up to 1.8 GPa, at which pressure it transforms to a new Xe clathrate phase stable up to 2.5 GPa before breaking down to ice VII plus sol...

Clathrate hydrates form the basis of a general model of biomolecule hydration. In clathrate hydrate crystal structures, the size of hydrogen-bonded water rings is highly constrained to five members. The clathrate hydrate model predicts that the size of water rings near biomolecule surfaces is similarly constrained to five members. This report describes a test of this model of biomolecule hydrat...

Program Scope Clathrate hydrates are inclusion compounds in which guest molecules occupy the cages formed by a hydrogen-bonded water network [1]. Solid gas clathrate hydrates generally form at high pressures and temperatures near or even above the ice point. Pure hydrogen hydrates have been reported to form cubic structure II hydrates under extreme conditions (200 MPa at 280 K) [2]. We have rec...

Clathrate hydrates are inclusion compounds in which guest molecules are trapped in a host lattice formed by water molecules. They are considered an interesting option for future energy supply and storage technologies. In the current paper, time lapse 3D micro computed tomographic (µCT) imaging with ice and tetrahydrofuran (THF) clathrate hydrate particles is carried out in conjunction with an a...

We report molecular simulation studies of the diffusion processes in ice and CO2 clathrate hydrates performed using classical potential models of water ~SPC/E! and carbon dioxide ~EPM2!. The diffusivity of H2O in ice is calculated to be 1.3310 218 m s at 200 K using molecular dynamics simulations, a result in good agreement with experimental data. We also computed the diffusivity of H2O and CO2...

We present 1–5 lm IR reflectance spectra of CO2 clathrate hydrates acquired under temperature and pressure conditions representative of the icy moons’ surfaces. The IR reflectance spectrum of the CO2 clathrate hydrates is similar to the water ice IR reflectance spectrum except for two main absorption bands corresponding to the CO2 guest molecule at 2.71 and 4.28 lm (3693 and 2334 cm!1). The spe...