The overtone spectra of H2O,D2O and mixtures of H2O in D2O ice

The overtones of the stretching vibration of OH and OD were measured in solid solutions of H₂O in D₂O over a wide range of concentration and temperatures. The observed frequencies and the overall shape of the spectra were related to excitations of single OH or OD bonds (bound excitations) and those involving neighboring OH bonds extending over the crystal (non-bound excitations). The observed large anharmonicity of the bound state is interpreted as due to a low lying barrier in the double minimum potential curve for the hydrogen motion.     

Radioluminescence of H2O and D2O ice spectral characteristics

The spectra of the radiofluorescence RF, afterglow AG and the thermoluminescence TL of H₂O and D₂O ice are reported. The RF spectrum of D₂O exhibits two bands, whereas for H₂O only one of these is seen. The spectrum of TL is different from that of RF and AG. It is argued that if any of these spectra are due to de-excitation of the triplet state of water it is that of the TL. This spectrum is peaked at 335 ± 3 nm and has a width of 46 nm.     

Infrared spectrum of D2O vibrationally decoupled in H2O ice Ic

The study of D₂O isolated in amorphous H₂O (ice Iv) has been extended to the determination of the bending mode frequency (1230 cm^?1) and to the measurement of the vibrational spectrum of the cubic ice phase (ice Ic). The vibrationally decoupled stretching frequencies (ν₁ = 2367 cm^?1 and ν₃ = 2444 cm^?1) for D₂O in the H₂O (Ic) have been obtained and an estimate of the exchange activation energy is given.     

Heat capacity and thermodynamic functions of MnBr2 · 4D2O and MnCl2 · 4D2O

The heat capacities of MnBr₂ · 4D₂O and MnCl₂ · 4D₂O have been experimentally determined from 1.4 to 300 K. The smoothed heat capacity and thermodynamic functions (H°_TH°₀) and S°_T are reported for the two compounds over the temperature range 10 to 300 K. The error in the thermodynamic functions at 10 K is estimated to be 3%. Additional error in the tabulated values arising from the heat capacity data above 10 K is thought to be less than 1%. A λ-shaped heat capacity anomaly was observed for MnCl₂ · 4D₂O at 48 K. The entropy associated with the anomaly is 1.2 ± 0.2 J/mole K.     

Two-photon excitation of h2o and D2O with a KrF laser (248 nm): photofragment fluorescence from OH and OD(A∑)

Photofragment fluorescence. From OH and OD(A ²∑⁺→X²π), has been observed following two-photon excitation of H₂O and D₂O in the gas phase with a KrF laser (248 nm). The rotational band contour of the OH fluorescence is the same as that observed following single-photon vacuum ultraviolet photolysis of H₂O at 123.6 nm.     

Capture of asymmetric top dipolar molecules by ions: Rate constants for capture of H2O, HDO, and D2O by arbitrary ions

The capture of rotationally state-selected and unselected asymmetric top polar molecules by ions is investigated. Analytical expressions (for all rotational states up to j = 2) of capture rate constants in the perturbed-rotor second-order limit are derived for application to low temperature conditions. Approximate analytical representations over wider temperature ranges are also given for rotationally unselected molecules. The capture of H₂O, D₂O, and HDO by arbitrary ions is chosen for demonstration of the approach. Capture rate constants for the about 60 reactions of H₂O with ions listed in the UMIST 2006 data base for astrochemistry are calculated, compared with experimental data, and represented in the format k_cap(T) ≈ c₁ + c₂(T/300 K)^−1/2. The parameters c₁ and c₂ can be predicted in a very simple way. The approach allows one to identify capture-controlled mechanisms and/or to trace experimental artifacts. The approach applies equally well to the capture of symmetric top and linear dipole molecules by arbitrary ions.     

Multiphoton ionization vibrational state selection of H2O, D2O and HDO

We present a study of single color (2 + 1) resonance-enhanced multiphoton ionization (REMPI) of H₂O, D₂O, and HDO via several Rydberg states lying in the energy range from 80 000 to 86 000 cm⁻¹. Photoelectron spectra (PES) show that the corresponding cations can be vibrationally state-selected for most vibrational states. The exception is the bend of H₂O⁺ and HDO⁺, where mixing in the REMPI intermediate level results in weak ion intensity and only 50% state purity.     

Deuteron relaxation study of D2O motions in a lyotropic liquid crystal

The water molecules adsorbed at the soap—water interface in the mesophases of potassium laurate—D₂O system reorient rapidly while diffusing along the interface; our results also suggest that the dynamical behaviour of the aqueous and paraffinic media are strongly correlated.     

Methane synthesis from CO/H2O mixture on supported nickel catalysts, II. Surface species in CO?H2 and CO?D2O interaction by IR spectroscopy

The species resulting in CO, CO+H₂ or CO+D₂O adsorption on supported Ni catalysts were followed by IR spectroscopy and their role in methane synthesis mechanism is discussed.

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- , CO, CO+H₂ CO+D₂O . .

     

Zur quantitativen Bestimmung Kleiner Mengen Wasser (H2O) in schwerem Wasser (D2O)

Ohne Zusammenfassung     

Spektralphotometrische Bestimmung von schwerem Wasser in H2O/D2O-Gemischen im nahen Infrarot

Zusammenfassung Zur Bestimmung von D₂O in H₂O/D₂O-Gemischen mit Hilfe der IR-Absorption werden 3 verschiedene Methoden beschrieben, die sich in der benutzten Wellenlänge, dem Konzentrationsbereich und der erreichbaren Genauigkeit unterscheiden: 2500 nm: 99–100 Mol-% D₂O, ±0,001%; 1670 nm: 0–20 Mol-% D₂O, ±0,02%; 1368nm: 0–100% D₂O, ±0,1%. Die Methoden sind einfach, schnell und haben sich in mehrjähriger Erfahrung bewährt.

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Spectrophotometric determination of heavy water in H₂O/D₂O mixtures in the near infrared

Three different methods are described for the determination of D₂O in H₂O/D₂O mixtures by means of IR absorption. Wave-lengths, concentration ranges and accuracies are as follows: 2500 nm: 99–100 Mol-% D₂O, ±0.001%; 1670 nm: 0–20 Mol-% D₂O, ±0.02%; 1368 nm: 0–100% D₂O, ±0.1%. The methods are simple and rapid and have been successfully used for several years.

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Für die beratende Mithilfe zu dieser Arbeit bin ich Herrn Dr. P. Baertschi zu Dank verpflichtet.     

Study of the vibrational spectra of SO2, H2O and D2O using the U(4) algebraic model

Using the U(4) algebraic model, in this work we report a study of the vibrational spectra of SO₂, H₂0¹⁸ and D₂O¹⁶. The inclusion of intermode couplings in algebraic models has been stated to give a deep insight into detailed spectroscopy for these bent XY₂ molecules. Improved set of algebraic parameters has been reported to provide improved RMS deviations for these molecules.     

On the ESR spectra of matrix-stabilized hydronium radicals H3O and D3O

The results of INDO calculations do not support the discovery of the H₃O free radical.     

Luminescence in near-thermal charge exchange. II. He+ + H2O and He+ + D2O

An ICR spectrometer fitted with synchronous photon counting equipment is used to study the emission produced by near-thermal (? 0.1 eV) collisions between He⁺ and H₂O (D₂). Within the investigated wavelength region, 185 to 500 nm, the only significant emission features are the A³Π (υ' ? 3) → X³Σ^? bands in OH⁺ and OD⁺, and the A²Σ⁺ → X²Π(0.0) band in OH and, possibly, in OD. The corresponding excitation rate constants represent only ? 2% of the total He⁺/H₂O (D₂O) charge transfer. The resonant electron-jump model for thermal-energy charge exchange is discussed in the light of recent information on the He⁺/H₂O reaction and on the excited states of H₂O⁺ and their excitation by electron and photon impact on H₂O (D₂O).     

Collision and magnetic field effects on time-resolved fluorescence of D2CO excited by a N2 laser

Time-resolved fluorescence spectra of D₂CO were measured as a funtion of sample pressure. The result indicates the occurence of rotational and vibrational relaxation between excited states. The Magnetic field effect on fluorescence from D₂CO excited by a N₂ laser depends on the nature of the vibronic levels.     

A study of structural transformation rates in NiTiF6·6D2O

The progression rate versus temperature for the supercooled structural transformation in NiTiF₆·6D₂O is compared to that of NiTiF₆·6H₂O. Energy parameters are obtained from a fit to a nucleation and growth model. Deuteration lowers the critical temperature by ≈ 14 K, and a second transition seen in the hydrated salt is not unambiguously observed.     

NMR study of phase separation in D2O/ethanol solutions of poly(N-isopropylmethacrylamide) induced by solvent composition and temperature

¹H and ¹³C NMR spectroscopies were applied to investigate phase separation in solutions of poly(N-isopropylmethacrylamide) (PIPMAm) in D₂O/ethanol (EtOH) mixtures induced by solvent composition (cononsolvency) and temperature. Effects of EtOH content in D₂O/EtOH mixtures and temperature on the appearance and extent of the phase separation were characterized. Differences in mesoglobules formed during the phase separation induced by cononsolvency and temperature were found. For temperature-induced phase separation, ¹³C spin-spin relaxation times showed that besides the free EtOH expelled from the PIPMAm mesoglobules, there are also EtOH molecules bound in these mesoglobules. On the other hand, virtually no bound EtOH molecules were detected for mesoglobules formed as a consequence of the cononsolvency. For PIPMAm random copolymers containing negatively charged methacrylate units the phase separation induced by solvent composition was not observed.     

Eine Methode zur Bestimmung von D2O in Wasser im nahen IR-Gebiet

Ohne Zusammenfassung     

Dissociation constants of Br∅nsted acids in D2O and H2O: studies on polyaza and polyoxa-polyaza macrocycles and a general correlation

Using data on a series of polyaza and polyoxa-polyaza macrocyclic compounds, a satisfactory linear correlation was established between the dissociation constants of their acid forms obtained in deuterium oxide (pK_D) and in water (pK_H). The isotopic effect, ΔpK=pK_D - pK_H, increases with increasing pK, being larger for the weaker acids. The pK_D vs. pK_H correlation may be used to determine pK_D or pK_H values when one of the constants is known; the statistical errors of the estimates are not significatively higher than those of the experimental determinations. By including data available in the literature for a series of different acids (mineral and carboxylic acids, phenols, protonated amines, amino acids, etc.; a total of 138 pairs of data for 70 different compounds), a good general pK_D vs. pK_H correlation was also obtained (correlation coefficient 0.998), showing that the dependence of the isotopic effect on the nature of the acid is not as important as previous studies, based on limited and not always satisfactory Δpk vs. pK_H correlations, suggested.