Small Amounts Of H2O Research Articles

The Impact of Li Grain Size on Coulombic Efficiency in Li Batteries.

One of the most promising means to increase the energy density of state-of-the-art lithium Li-ion batteries is to replace the graphite anode with a Li metal anode. While the direct use of Li metal may be highly advantageous, at present its practical application is limited by issues related to dendrite growth and low Coulombic efficiency, CE. Here operando electrochemical scanning transmission electron microscopy (STEM) is used to directly image the deposition/stripping of Li at the anode-electrolyte interface in a Li-based battery. A non-aqueous electrolyte containing small amounts of H2O as an additive results in remarkably different deposition/stripping properties as compared to the “dry” electrolyte when operated under identical electrochemical conditions. The electrolyte with the additive deposits more Li during the first cycle, with the grain sizes of the Li deposits being significantly larger and more variable. The stripping of the Li upon discharge is also more complete, i.e., there is a higher cycling CE. This suggests that larger grain sizes are indicative of better performance by leading to more uniform Li deposition and an overall decrease in the formation of Li dendrites and side reactions with electrolyte components, thus potentially paving the way for the direct use of Li metal in battery technologies.

The Effect of H2O and Pressure on Multiple Saturation and Liquid Lines of Descent in Basalt from the Shatsky Rise

Abstract Numerous models have been developed to simulate the reaction of magmas to changes of thermodynamic variables, such as pressure, temperature, oxygen fugacity, and water activity. However, the extensive experimental database still lacks information on the distinct effect of small amounts of H2O on olivine + plagioclase + clinopyroxene cotectic crystallization in tholeiitic basalt. We present an experimental study addressing the effects of pressure (at 100, 200, 400, and 700 MPa) and small amounts of H2O on phase relations and liquid lines of descent in three tholeiitic basalts representing different evolutionary stages of the Shatsky Rise oceanic plateau magmatic system (compositions AH6, AH3, and AH5 with 8·6, 8·0, and 6·4 wt % MgO, respectively). Two experimental approaches (dry and low H2O) are designed to maintain contrasting H2O activities during crystallization using (1) graphite–platinum double capsules to perform nearly anhydrous experiments (<0·15 wt % H2O in the melt) and (2) Fe pre-saturated Au20Pd80 capsules to obtain low melt H2O contents ranging from 0·4 to 1·1 wt % H2O. Under dry conditions, at lower pressures (≤400 MPa), the crystallization in the MgO-rich AH6 and intermediate AH3 basalts follows the typical sequence of tholeiitic differentiation with olivine crystallization at the liquidus followed by olivine + plagioclase and olivine + plagioclase + clinopyroxene. Both basalts are close to multiple saturation at pressures between 400 and 700 MPa. At high pressure (700 MPa) the crystallization sequence is reversed, starting with clinopyroxene at the liquidus. Under low-H2O conditions, AH6 and AH3 are very close to multiple saturation, even at the low pressures of 100 and 200 MPa, and the reversed crystallization sequence (clinopyroxene, plagioclase + clinopyroxene, olivine + plagioclase + clinopyroxene) is observed already at 400 MPa. In contrast to the two more MgO-rich basalts, in the most evolved AH5 basalt, clinopyroxene is the liquidus phase at all investigated pressures and under both dry and low-H2O conditions, followed by crystallization of plagioclase + clinopyroxene and olivine + plagioclase + clinopyroxene. The most striking observation in our experiments is that the stability of clinopyroxene increases not only with pressure increase but also in the presence of small amounts of H2O (when compared with dry counterparts at similar pressures). Small amounts of H2O increase the proportion of clinopyroxene in the olivine + plagioclase + clinopyroxene phase assemblage. Our experiments clearly show that the effect of adding 0·4 wt % H2O to cotectic melt compositions (e.g. CaO/Al2O3 ratio at a given MgO) is similar to that caused by an increase of pressure from 100 to ∼ 300 MPa. This implies that small amounts of H2O can lead to significant overestimation of cotectic crystallization pressures (by up to 300 MPa) and that H2O contents need to be taken into account in geobarometric models. Our new experiments emphasize the role of low melt H2O contents in stabilizing clinopyroxene and provide some new insights into the problem of the ‘pyroxene paradox’. The apparent mantle pressures obtained for some mid-ocean ridge basalts using ‘dry’ geobarometric approaches can actually represent depths within the lower crust, if small amounts of H2O are present. The application of our experimental data to natural Shatsky Rise basalts implies that the magmas record partial crystallization processes occurring mainly at low pressure (100 MPa), corresponding to depths of ∼3 km beneath the former spreading center, although the more primitive lavas show evidence of differentiation in a deeper reservoir at ∼14 km depth (400 MPa).

Improved Synthesis of a Zirconium(IV) Muconate Metal–Organic Framework: Characterization, Stability and Gas Sorption Properties

AbstractThe formerly reported ZrIV trans,trans‐muconate framework material (1) was synthesized by using an improved synthetic protocol. Instead of using the noncommercial Zr6‐methacrylate oxido cluster as the metal source, the same MOF was successfully synthesized by using commercially available ZrCl4 as the Zr source. Small amounts of H2O (1‐H2O‐AS; AS = as‐synthesized) or concd. aqueous HCl (1‐HCl‐AS) were used as additives in N,N‐dimethylformamide (DMF) in order to enhance the crystallinity of the compounds. The guest molecules were removed from the pores by heating the as‐synthesized compounds under vacuum, resulting in the empty‐pore forms of the compounds. The as‐synthesized and thermally activated compounds were characterized by X‐ray powder diffraction (XRPD), Fourier transform infrared (FTIR), thermogravimetric (TG) and elemental analyses. Thermogravimetric analyses suggest that the two compounds are stable up to ca. 250 °C in an air atmosphere. As verified by the XRPD experiments, the 1‐HCl compounds gradually lose their crystallinity when exposed to water and moisture. As confirmed by the N2 sorption analyses, the optimally activated 1‐HCl compound displayed a BET surface area of 557 m2 g–1, which is lower than the isostructural UiO‐66 (950 m2 g–1) but it is close to the literature value (705 m2 g–1). The moderate physiochemical stability paired with considerable porosity renders the material a promising candidate for gas storage and separation.

ChemInform Abstract: Crystal Structures of Na2SeO4·1.5H2O and Na2SeO4·10H2O.

AbstractNa2SeO4·1.5H2O (I) and Na2SeO4·10H2O (II) are precipitated from a ≈60 wt% H2SeO4 solution containing excess Na2CO3 solution, drying in air, and redissolution of the anhydrous product in small amounts of H2O followed by evaporation at 300, 293, and 280 K.

ChemInform Abstract: Syntheses and Structures of Na2Mg3(OH)2 (SO4)3·4H2O and K2Mg3(OH)2 (SO4)3·2H2O.

AbstractThe title compounds are prepared from stoichiometric mixtures of MgO, MgSO4, Na2SO4, or K2SO4 with small amounts of H2O by heating to 150 °C for 12 h and drying.

Segregation of magmatic fluids and their potential in the mobilization of platinum-group elements in the South Kawishiwi Intrusion, Duluth Complex, Minnesota — Evidence from petrography, apatite geochemistry and coexisting fluid and melt inclusions

Pegmatitic and other felsic rock pockets and dike-like intrusions are abundant in the South Kawishiwi Intrusion of the Duluth Complex, including the basal, Cu–Ni–PGE mineralized units. These occurrences are found as pockets, pods or as veins and contain abundant accessory apatite and quartz. Quartz hosts primary fluid inclusions as well as silicate melt inclusions. Combined microthermometry and Raman spectroscopy helped to determine the bulk composition of primary fluid inclusions that are CO2-rich (95mol%) and contain small amounts of H2O (4.5mol%), CH4 (0.4mol%) and trace N2, respectively. This combined technique also made it possible to measure total homogenization temperatures of the inclusions (Thtot=~225±10°C), otherwise not detectable during microthermometry. Silicate melt inclusions have been quenched to produce homogeneous glasses corresponding to the original melt. Composition of the entrapped melt is granitoid, peraluminous and is very poor in mafic components. We interpret the melt as a product of partial melting of the footwall rocks due to the contact effect of the South Kawishiwi Intrusion. The presence of CO2 in the vapor bubbles of the quenched melt inclusions and petrographic evidence suggest that the fluid and melt inclusion assemblages are coeval. The composition of the fluid and melt phase implies that the fluid originates from the mafic magma of the South Kawishiwi Intrusion and the fluid and melt phases coexisted as a heterogeneous melt–fluid system until entrapment of the inclusions.Coexistence of primary fluid and melt inclusions makes it possible to calculate a minimum entrapment pressure (~1.7kbar) and thus estimate formation depth (~5.8km) for the inclusions. Chlorine is suggested to behave compatibly in the silicate melt phase in the fluid–melt system represented by the inclusions, indicated by the high (up to 0.3%) Cl-concentrations of the silicate melt and CO2-rich nature of the fluid.Apatite halogen-contents provide further details on the behavior of Cl. Apatite in pegmatitic pockets often has elevated Cl-concentrations compared to troctolitic rocks, suggesting enrichment of Cl with progressive crystallization. Systematic trends of Cl-loss at some differentiated melt pockets suggest that in some places Cl exsolved into a fluid phase and migrated away from its source. The segregation of Cl from the melt is probably inhibited by the presence of CO2-rich fluids until the last stages of crystallization, increasing the potential for the development of late-stage saline brines.Platinum-group minerals are often present in microcracks in silicate minerals, in late-stage differentiated sulfide veinlets and in association with chlorapatite, indicating the potential role of Cl-bearing fluids in the final distribution of PGEs.

Monte Carlo methods for radiative transfer in quasi-isothermal participating media

Based on the superposition principle, we propose in this study a Monte Carlo (MC) formulation for radiative transfer in quasi-isothermal media which consists in directly computing the difference between the actual radiative field and the equilibrium radiative field at the minimum temperature in the medium. This shift formulation is implemented for the prediction of radiative fluxes and volumetric powers in a combined free convection–radiation problem where a differentially heated cubical cavity is filled with air with a small amount of H2O and CO2. High resolution spectra are used to describe radiative properties of the gas in this 3D configuration. We show that, compared to the standard analog MC method, the shift approach leads to a huge saving of required computational times to reach a given convergence level. In addition, this approach is compared to reciprocal MC formulations and is shown to be more efficient for the prediction of wall fluxes but slightly less efficient for volumetric powers.

Comparative chemistries of CO and NO oxidation over RuO2(110): insights from first-principles thermodynamics and kinetics

In this contribution, we review our plane wave, supercell density functional theory-based comparisons of CO and NO oxidation chemistry at a RuO2(110) surface. Base metal oxides have long been of interest as catalysts for the oxidation of small molecules such as CO and NO, and understanding of their comparative chemistries on this scientifically important model metal oxide is important for understanding the factors of the control activity. The structures and energies of CO x and NO x adsorbates on the RuO2(110) surface are contrasted, and their thermodynamic stability is quantified using a first-principles phase diagram approach. Distinctly different surface species dominate the two diagrams, reflecting the very different adsorptions and oxidation chemistries of CO and NO. Furthermore, H2O has a dramatic effect on the CO oxidation phase diagram that suggests a bicarbonate () as an important and unrecognised surface poison. These thermodynamic phase diagrams are complemented with mean-field microkinetic models that quantify absolute activity, provide a different window onto surface coverage and highlight the role of various surface species in poisoning activity. Consistent with experiment and previous simulations, CO oxidation is facile under conditions at which both CO and oxygen compete effectively for surface sites. Carbonates are unstable and unimportant to catalysis; facile bicarbonate formation poisons activity in the presence of even small amounts of H2O. An intermediate CO adsorption energy and weak CO2 binding make RuO2 much more effective in oxidising CO than NO, which adsorbs strongly and self-poisons even at high temperatures. RuO2 is predicted to be effective as a reversible NO adsorber. Finally, we reviewed the kinetics of several NO surface reactions and the pathway that may contribute to the decomposition of NO to N2 and N2O over partially reduced surfaces.

Interaction of carbon dioxide with Na-exchanged montmorillonite at pressures to 640 bars: Implications for CO2 sequestration

Na-exchanged montmorillonite swells upon interacting with CO2 under the conditions P(CO2)≤50bars, T=22–47°C, as shown by experiments in high-pressure environmental chambers using powder X-ray diffraction techniques. The amount of swelling depends on the initial H2O content of the montmorillonite. Maximum expansion, to 12.3Å, occurred in a sample with an initial d(001) of 11.3Å at P(CO2)=57bars. Thus, montmorillonite can expand by 9% in contact with CO2 when small amounts of H2O are present in the interlayer. Little to no expansion occurs for samples with an initial d(001)≤10.0Å or d(001)=12.3–12.5Å. The reaction with CO2 is complete by ∼50bars; increasing P(CO2) from 50 to 640bars did not result in any significant further increase of d(001). This work shows that a smectite-rich cap rock above a carbon sequestration reservoir may be significantly altered by reacting with CO2.

Deposition Mechanism and Electrical Property of CeO2 Thin Films by MOCVD with H2O Introduction

Cerium dioxide (CeO2) thin films are prepared by means of the metal organic chemical vapor deposition (MOCVD) using tetrakis (3-methyl-3-pentoxy) cerium with and without H2O vapor introduction. A large amount of H2O (more than 2 sccm) acts as an oxidant and as a result the deposition rate increases by up to four times at the deposition pressure of 2.0 Pa, leading to the temperature independence of the deposition rate. At the low deposition temperature of 270 åC, a small amount of H2O (0.1-0.2 sccm) suppresses the deposition because of its preferential occupation of the surface sites. The CeO2 film annealed at 600 åC in the oxidizing ambient shows steep C-V characteristics with no flat band voltage shift nor hysteresis.

Study on the Growth Mechanism of Electrolytic Chromium Coated Steel (ECCS)

The growth mechanism of ECCS was investigated by means of metallurgical microscope, SEM and XPS. The results show that the different modes of annealing and rolling have a remarkably effects on the surface morphology and grain size of TFS products. Compact surface Cr-coating of BA material with low porosity the grains are larger and coarser in comparison with that of CA material, while the evident microcracks are found in the surface Cr-coating of DR material. The chemical compositions of ECCS oxide film on steel mainly consist of CrOOH or Cr(OH)3 as the main composition, plus Cr2O3 in definite proportion and a small amount of H2O. Cr(OH)3 is mainly formed from cathodic films generated in the electroplating process. CrOOH as the intermediate resultant was formed in process of Cr(OH)3 loss water to generate Cr2O3.

ChemInform Abstract: Investigation of the Structural Properties of an Extended Series of Lanthanide Bis‐hydroxychlorides Ln(OH)2Cl (Ln: Nd—Lu, Except Pm and Sm).

AbstractThe title compounds are hydrothermally synthesized from LnCl3·6H2O in small amounts of H2O (autoclave, 220 °C, 21 d) and characterized by single crystal XRD, diffuse reflectance, FT‐IR, and FT‐Raman spectroscopy.

Mechanochemical Synthesis of LnCoO<sub>3</sub> (Ln: La, Pr, Dy)

Synthesis of lanthanoid cobaltates, LnCoO3 (Ln: La, Pr, Dy), via the mechanochemically prepared complex (oxy-)hydroxides has been studied. The hydroxides are prepared by grinding Co(OH)z or Co3O4 with Ln2O3 (Ln: La, Dy) or Pr6O11 in acetone containing a very small amount of H2O in LnCoO3 • 4H2O composition. The starting hydroxides act as the reactive grinding aids to each other. La2O3 and Co(OH)2 form the complex hydroxide, LaCo(OH)5, that is a sort of inorganic polymers having La-O-Co bond. The hydration affinity of trivalent Co3+ ions is not high enough to form complex hydroxide LaCo(OH)6. Then, the addition of H2O2 to the grinding liquid results in the formation of oxyhydroxide, LaCoO(OH)4. These (oxy-)hydroxides are directly converted to pseudo-tetragonal LaCoO3 at 600°C and rhombohedral LaCoO3 above 800°C without forming any by-product. The redox interaction between Co(OH)2 and Pr6O11, which shows the poor reactivity with Fe2O3, enables the formation of PrCoO(OH)4. Contrary, the reaction with Dy2O3 becomes poor.

Stability of Cubic Zirconia in a Granitic System Under High Pressure & Temperature

AbstractCubic zirconia is a well known, highly durable material with potential uses as an actinide host phase in ceramic waste forms and inert matrix fuels and in containers for very deep borehole disposal of some highly radioactive wastes. To investigate the behaviour of this material under the conditions of possible use, a cube of ∼ 2.5 mm edge was made from a single crystal of yttriastabilized cubic zirconia doped with 0.3 wt.% CeO2. The cube was enclosed in powdered granite within a gold capsule and a small amount of H2O added before sealing. The sealed capsule was held for 4 months in a cold-seal pressure vessel at a temperature of 780°C and a pressure 150 MPa, simulating both the conditions of a deep borehole disposal involving partial melting of the host rock and the conditions under which the actinide waste form might be encapsulated in granite prior to disposal. At the end of the experiment the quenched, largely glassy, sample was cut into thin slices and studied by optical microscopy, EMPA, SEM and cathodoluminescence methods. The results show that no corrosion of the zirconia crystal or reaction with the granite melt occurred and that no detectable diffusion of elements, including Ce, in or out of the zirconia took place on the timescale of the experiment. Consequently, it appears that cubic zirconia could perform most satisfactorily as both an actinide host waste form for encapsulation in solid granite for very deep disposal and as a container material for deep borehole disposal of highly radioactive wastes (HLW), including spent fuel.

Electrical conductivity measurements of brucite under crustal pressure and temperature conditions

Abstract Hydrous minerals are crucial because their occurrence is associated with seismic activity through the dehydration process that occurs in the earth’s crust and/or mantle. We have developed a technique to observe the dehydration reaction of brucite using electrical conductivity variation under sealed conditions. The electrical conductivity of brucite was measured as a function of temperature. The confining pressure for the measurements was 1 GPa, which represents that of the lower crust. Two types of remarkable electrical conductivity variation were observed. During the first heating, the conductivity of the sample showed a linear variation below 700 K, as was expected from the Arrhenius equation. Once the temperature was increased to near the dehydration boundary, the sample showed a high conductivity. Even though only a small amount of H2O was formed after dehydration, bulk conductivity of the sample varied greatly, presumably caused by a combination of the presence of coexisting solid and fluid phases and a mixed electronic and ionic conduction mechanism operating in the sample.

Tetrahedrally coordinated boron in tourmalines from the liddicoatite-elbaite series from Madagascar: Structure, chemistry, and infrared spectroscopic studies

Four colorless tourmalines of the liddicoatite-elbaite series from pegmatites from Anjanabonoina, Madagascar, have been characterized by crystal-structure determination and by chemical analyses. Optimized formulae range from X(Ca0.57Na0.29□0.14) Y(Al1.41Li1.33Mn2+0.07□0.19) ZAl6T(Si5.86B0.14)O18 (BO3)3V(OH)3.00W[F0.76(OH)0.24] [a = 15.8322(3), c = 7.1034(3) Å] to X(Na0.46Ca0.30□0.24) Y(Al1.82Li0.89Fe2+0.01 Mn2+0.01□0.27) ZAl6T(Si5.56B0.44)O18 (BO3)3V(OH)3.00W[(OH)0.50F0.50] [a = 15.8095(9), c = 7.0941(8) Å] (R = 1.3.1.7%). There is a high negative correlation (r2 = 0.984) between the <T-O> bond-lengths (~1.618.1.614 Å) and the amount of IVB (from the optimized formulae). Similar to the olenites (from Koralpe, Austria) the liddicoatite-elbaite samples show a positive correlation between the Al occupancy at the Y site and IVB (r2 = 0.988). Short-range order configurations show that the presence of IVB is coupled with the occupancy of (Al2Li) and (Al2□) at the Y site. The structural formulae of the Al-rich tourmalines from Anjanabonoina, Madagascar, show ~ ⃞0.2 (vacancies) on the Y site. We believe that short-range order configurations with Y(Al2□) are responsible for these vacancies. Hence, an oft-used calculation of the Li content by difference on the Y site may be problematic for Al-rich tourmalines (olenite, elbaite, rossmanite). Fourier transform infrared (FTIR) spectra were recorded from the most IVB-rich tourmaline sample. The bands around 5195 and 5380 cm-1 can be assigned to H2O. Because these bands still could be observed in FTIR spectra at temperatures from -150 to +600 °C, it seems unlikely that they result from H2O in fluid inclusions. Interestingly, another FTIR spectrum from a dravite in which the X site is filled completely with Na, does not show bands at ~5200 and ~5400 cm-1. Although not definitive, the resulting spectra are consistent with small amounts of H2O at the X site of the elbaite. The rare-earth element (REE) pattern of the B-rich elbaite (ΣREE: ~150 ppm) demonstrates that this sample is strongly enriched in LREEs compared to HREEs and exhibits a negative Eu anomaly. This sample shows the strongest enrichment of LREEs and a high LaN/YbN ratio of ~351, which seems to confirm an important role of the fractional crystallization process.

NON-PREMIXED IGNITION BY VITIATED AIR IN COUNTERFLOW CONFIGURATIONS

ABSTRACT Ignition studies have been conducted in counterflow configurations in recent years by using heated air as the ignition source. In the present investigation, an alternative methodology has being advanced for studying ignition, by utilizing vitiated air that is produced from the oxidation of ultra-lean H2/air mixtures supplied from one burner. Non-premixed ignition is achieved by counter-flowing the hot vitiated air against a fuel-containing jet. The ultra-lean H2/air mixtures are oxidized on a catalyst positioned at the burner exit, allowing thus for the effective variation of the temperature of the hot gases, which are mainly composed by N2, excess O2, small amounts of H2O, and negligible amounts of radical species. Thus, the heat release of the H2 oxidation serves as the ignition source and eliminates the need of heating the air. This new methodology was tested for non-premixed ignition of H2 and H2-enriched CO. H2 and CO were studied first, given that the kinetics of these fuels, constitute the fundamental “building blocks” of the hydrocarbons oxidation kinetics. For the H2 studies, the ignition temperatures were measured for global strain rates varying between 100 and 250 s−1 and mole fractions of H2 in the (H2 + N2) stream varying between 10–60%. Similar studies were conducted for non-premixed H2-enriched CO, with H2 molar fractions ranging from 0.3–3% in the fuel stream. The fuel stream was not diluted with N2 in these studies, given the relatively low ignition propensity of CO, and the need to avoid excessively high ignition temperatures as they could impact the performance of the catalyst and its supporting ceramic material. The present experimental results compare favorably with previously reported ones in similar configurations, providing thus confidence in the proposed ignition methodology. Agreements with numerical predictions were partially satisfactory.

Vibration properties of low-fraction hydrogen in deuterium ices

Inelastic incoherent neutron scattering spectra of D2O high-density amorphous (hda) ice, ice-VIII and ice-II mixed with small amount of H2O (<5%) have been measured recently on high-energy transfer spectrometer at Rutherford Appleton Laboratory (UK). The hydrogen atom on D2O ice lattices has three distinguished vibrational modes, two bending at low frequencies and one stretching at high frequencies and their frequencies are slightly different for different phases of ice. It was found that the lower one of the bending modes is located at ~95 meV for hda-ice, at ~95 meV for ice-VIII and at ~96 meV for ice-II and they are all lower than the value of 104 meV for ice-Ih. It was also measured that the O-D and O-H covalent bond stretching modes of ice-VIII are at ~315 and ~425 meV, ice-II at 307 and ~415 meV, hda-ice at 312 and ~418 meV, respectively. They are significantly higher than the values of ice-Ih at ~299 and ~406 meV, respectively.

Aluminum position in Rb-feldspar as determined by X-ray photoelectron spectroscopy.

Al/Si configurations in some natural and synthetic Rb-feldspars have been examined carefully by EMPA and XPS analyses. Our results indicate that a small amount of H2O and excess Si and Al are incorporated in hydrothermally synthesized Rb-feldspar. The quantities of excess Al are 0.056 atoms per formula unit and are negatively correlated with those of the Rb, suggesting the presence of excess Al occupying non-tetrahedral sites in feldspar structures. This leads to incorporation of Al(Al3Si)O8 endmember into Rb-feldspars, estimated as one appropriate endmember indication for unusual chemistry of feldspars. In addition, Si2p, Al2p and O1s XPS signals of Rb-feldspars shift drastically toward the higher energy side than those of any natural feldspars. These provide conclusive evidence not only for existence of perceptible excess Si and Al, but also for Al at both extra-framework and tetrahedral sites in feldspar structures.

Defect hydrogen vibrations in various phases deuterium ice

The inelastic incoherent neutron scattering spectra of D2O mixed with a small amount of H2O (5% by weight) high density amorphous (hda) ice, ice-VIII, and ice-II have been measured on HET spectrometer at Rutherford Appleton Laboratory (UK). The hydrogen atom in D2O ice lattice has three distinguished vibrations: two modes normal to the O–––H bond at lower frequency and a stretching mode along the O–H bond at higher frequency. For different ice phases these frequencies are different, it was found that the lower defect mode is at ∼97 meV for ice-II, at about 95 meV for hda-ice and ice-VIII, and they are all lower than the value of 105 meV for ice-Ih. The O–H stretching modes are at 415 meV for ice-II, at 418 meV for hda-ice, and at 425 meV for ice-VIII, which all are much larger than the value for ice-Ih, 406 meV. It was also found that O–D stretching modes in D2O ice-VIII is centered at ∼320 meV which is significantly higher than the corresponding value of ∼305 meV for ice-Ih.