100 ps far-infrared laser pulses from optically pumped D2O

In this paper we report the generation of ultrashort far-infrared laser pulses with durations less than 100 ps, powers exceeding 200 kW and intensities of more than 1.5 MW/cm². Far-infrared radiation was produced via stimulated resonance Raman scattering using a high-pressure CO₂-laser as pump source and the heavy water isotopes D₂¹⁶O and D₂¹⁸O as far-infrared laser media. Pulses achieved from this laser system were detected by a novel type of detector, sensitive over a broad spectral range from the far-infrared to the visible, basing on quasiparticle heating in a strip-line structured YBa₂Cu₃O_7−δ thin film.     

High-resolution infrared spectrum of CH2D2: The ν3 fundamental band at 7 μm

The infrared spectrum of CH₂D₂ has been recorded in the region of 1345 to 1561 cm^?1 with a resolution of 0.030 to 0.026 cm^?1. Most of the observed lines have been assigned to transitions of the ν₃ band of CH₂D₂. However, 114 lines have been identified as transitions of the ν₂ band of H₂¹⁶O whose band origin has been directly determined to be 1594.7472 ± 0.0030 cm^?1. A few weak lines, probably belonging to the ν₅ fundamental of CH₂D₂, remain unassigned. The band center ν = 1435.1326 ± 0.0030 cm^?1 and a set of upper state constants were obtained for the ν₃ band of CH₂D₂. Although a slight perturbation was noticed in the ν₃ band, all wavenumbers have been fitted with a standard deviation of 3.8 × 10^?3 cm^?1.     

Absorptionsspektrum des Ce3+-Ions und Schwingungsspektrum im CeCl3·7H2O und CeCl3·7D2O

The absorption spectra of CeCl₃·7 H₂O, LaCl₃·7 H₂O, CeCl₃·7 D₂O and LaCl₃·7 D₂O have been measured at low temperatures in the region of the 4 f→4 f infrared transitions. The energy levels of the Ce³⁺-ion in these compounds have been derived. The infrared phonon transitions have also been determined from the reflection spectra of these crystals measured in the region between 4000 cm^?1 and 50 cm^?1. Some of the energy levels of the Ce³⁺-ions in the deuterated crystals are shifted for about 10 wavenumbers against those in CeCl₃·7 H₂O. These shifts are probably due to an interaction of the electronic levels with resonant phonon-states in one or the other of the two compounds.     

Thermal release of trapped deuterium from silica injected by 80-keV D+ ion implantation and RF D2 plasma

When silica is irradiated by 80-keV D⁺ ions or RF plasma of D₂ gas, deuterium is trapped in the silica forming Si-OD bonds. The deuterium, trapped as OD bonds, is desorbed from the silica upon heating to form some release products. The thermal detrapping process corresponds to decrease of OD bonds and was studied by measurement of infrared Fourier transform spectroscopy (FTIR). The release products HDO, D₂O, HD, and D₂ were measured by quadrupole mass spectroscopy (QMS). The detrapping and release processes of trapped deuterium were studied by simultaneous measurement of FTIR and QMS. Since the release spectra of HDO, D₂O, HD, and/or D₂ correspond to the decrease spectra of OD bonds, these release products are formed by thermal decomposition of OD bonds. The formation of water (HDO, D₂O) and hydrogen (HD, D₂) depends upon concentration of pre-existing OH bonds and deuterium injection methods (80-keV D⁺ implantation or RF D₂ plasma irradiation).     

IR-Spectra of M2UO2F4.H2O Complexes

This work is devoted to the study of and Rb₂UO₂F₄.H₂O and Cs₂UO₂F₄. H₂O IR-spectra with the aim of obtaining a set of vibration frequencies characterising M₂U0₂F₄.H₂O complexe elucidating the role and nature of water bonds in the structures of the above-mentioned compounds; and receiving preliminary information on the structure of M₂UO₂F₄.H₂O. The investigated compounds were synthesized in accord with our previous paper¹. M₂UO₂D₂O and M₂UO₂F₄.HDO were obtained by recrystallizing M₂UO₂F₄.H₂O from D₂O and HDO respectively     

The quenching of Pb(6p 2 1 D 2) atoms in collisions with molecules

The collisions of metastable Pb(6p ^{2 1} D ₂) atoms with various molecules were studied by the diagnostics of radiation from a hollow cathode lamp and a laser on lead vapor. Experiments were performed for a gas flow of lead atoms with argon. The Pb(6p ^{2 1} D ₂) states were excited in a gas discharge in the presence of reagent gas molecules. The absolute rate constants for the quenching and chemical reactions of lead atoms in the ground and excited states were determined. The quantum efficiency of chemical reactions was close to one for the N₂O, CH₂Cl₂, SF₆, and CuBr molecules. Long-lived chemical compounds were formed in these reactions.     

Relative equilibria of D2H + and H2D+

Relative equilibria of molecules are classical trajectories corresponding to steady rotations about stationary axes during which the shape of the molecule does not change. They can be used to explain and predict features of quantum spectra at high values of the total angular momentum J in much the same way that absolute equilibria are used at low J. This paper gives a classification of the symmetry types of relative equilibria of AB₂ molecules and computes the relative equilibria bifurcation diagrams and normal mode frequencies for D₂H⁺ and H₂D⁺. These are then fed into a harmonic quantization procedure to produce a number of predictions concerning the structures of energy level clusters and their rearrangements as J increases. In particular the formation of doublet pairs is predicted for H₂D⁺ from J ≈ 26.     

Vibrational Spectra and Structure of Potassium Alum Kal(SO4)2·12[(H2O) x (D2O)1−x ]

The IR spectra and polarization Raman spectra of Kal(SO₄)₂·12(H₂O) and Kal(SO₄)₂·12[H₂O)_0.3(D₂O)_0.7] crystals at 93 K and room temperature have been obtained experimentally. The vibrational spectra of structural elements of potassium alum — the complexes [Al(H₂O)₆ ³⁺ and [Al(D₂O)₆]³⁺ — have been calculated. The vibrational spectra have been interpreted based on the calculation and factor-group analysis data. The spectral data obtained point to the fact that, in the crystals considered, the sulfate ions are partially disordered and there exist two crystallographically different types of water molecules.     

Structure and proton mobility in the defect pyrochlore (H2O)xH2Ta2O6

The structure of the defect pyrochlore (D₂O)_0.38D₂Ta₂O₆ has been determined by powder neutron diffraction. The deuteroxyl deuterons randomly occupy sites ∼ 1.04 Å from the framework oxygens. The water molecules are situated on sites at the centre of the defect pyrochlore cavity, 8b position of Fd3m, and the O_W-D_W bonds lengths are 0.97 Å. A pulsed solid state N.M.R. study of (H₂O)_0.42H₂Ta₂O₆ has shown that this material is a reasonable proton conductor with a room temperature diffusion co-efficient of ∼ 10^-9 cm² s^-1.     

Stark-Effekt-Untersuchungen der Hyperfeinstruktur der 5s25d2D3/2- und 5s25d2D3/2-Terme im In I-Spektrum

The level-crossing technique with combined electric and magnetic fields was used to investigate the hyperfine structure of the 5s ²5d ² D _3/2- and 5s ²6d ² D _3/2-stedes of the In I-spectrum. From the shifts of the level-crossing signals due to the Stark effect of the electric field the Stark constantsβ of both states were deduced: 5s ²5d ² D _3/2: ¦β¦=0.33(3) Mc/(kV/cm)² 5s ²6d ² D _3/2: ¦β¦=6(1) Mc/(kV/cm)². By theoretical calculations with wave functions of the Coulomb approximation one can show, that the Stark effect in both states is mainly due to admixtures of the 5s ²6p- resp.5s ²7p-configuration.     

Far-infrared absorption intensities of H2O and D2O in C6H6

Far-i.r. absorption intensities have been measured for H₂O and D₂O in C₆H₆ solutions. Beer's law plots were found to be nonlinear. From the plots, the equilibrium constants of dimer formation in benzene were estimated to be 2.4M^-1 and 3.3M^-1 for H₂O and D₂O at 20°C, respectively. Based on Onsager's reaction field and including explicitly the effect of differences in molecular size between solute and solvent molecules, the internal moment of a water molecule and the volume ratio of a molecule to a cavity were estimated from the integrated absorption intensity of a D₂O monomer in C₆H₆ as 1.98 D and 0.7, respectively     

The determination of the NMR gyromagnetic ratio of deuteron in D2O

Results of measurement of the ratio of the nuclear resonance frequencies of deuterons in D₂O and of protons in H₂O are given. From these measurements the gyromagnetic ratio of deuteron in D₂O is evaluated as _d/2=6·535670(23) (10² HzG^–1). The experimental equipment and method are described and the results are discussed in comparison with the measurements of other authors.Na Slovance 2, Praha 8, Czechoslovakia.     

Absolute photoabsorption cross sections for H2O and D2O from λ 180–790 Å

Absolute photoabsorption cross sections for H₂O and D₂O have been measured photoelectrically from λλ 180 to 790 Å using synchrotron radiation. The cross sections increase smoothly with wavelength to ～λ610 Å, with both H₂O and D₂O displaying a broad absorption band extending above a nearly linear background from λλ 400 to 490 Å. The continuum has a maximum of ～ 22.5 Mb at λ 640 Å. Above λ 615 Å, superimposed on the continuum, a diffuse structure appears which is similar to the vibrational structure of the ²B₂ states of H₂O⁺ and D₂O⁺ as observed in photoelectron spectra. The structure is believed to arise from excitation of a 1b₂ electron to the vibrational levels of a Rydberg orbital with n¹ ≈ 2.64.     

Lande g-Factors of 7d1D2 and 8d1D2 States of Mercury

Lande g-factors of 5d¹⁰6s7d¹D₂(1.0155) and 5d¹⁰6s8d¹D₂(1.0285) atomic mercury levels have been determined using quantum beats method after electron pulse excitation.     

Multinuclear study of RF losses in NaCl/D2O solutions

The RF losses in NMR experiments on ionic solutions have been investigated by multi-NMR. The change of π/2 pulse length (PW)₉₀ for²³Na,³⁵Cl,²D,¹⁷O and¹H nuclei in NaCl/D₂O solutions has been systematically studied. Quantitative relation between (PW)₉₀ values and the sample specific conductivity σ has been established. The increase in (PW)₉₀ values has been experimentally correlated to the reduction of the signal-to-noise ratio through¹⁷O measurements.     

FT-IR Study of the Interaction Between H2O,D2O,HOD, and Pyridines

Abstract

The complexes between H₂O, D₂O, HOD and pyridine have been studied in 1,2-dichloroethane by FT-IR spectrometry. Equal splittings of the stretching bands of H₂O and D₂O about their uncoupled vibrations are observed. The coupling between the asymmetric and symmetric vibrations reaches a value of zero when the band separation is greater than 500 cm^?1 for the OH vibrations and 365 cm^?1 for the OD vibrations. The v_OH stretching frequencies of the HOD ‥ complexes and the v_OD stretching frequencies of the DOH‥ complexes increase by complex formation. These features are explained by an electronic reorganization within the hydrogen bond.     

Synthesis and characterization of fast-decaying bluish green phosphors of Tb3+-doped CaSi2O2N2 for 2D/3D plasma display panels

Oxynitride phosphor powders comprising of CaSi₂O₂N₂ doped with Tb³⁺ were successfully synthesized using a high-temperature solid-state reaction method. The experimentally determined photoluminescence (PL) properties of the produced phosphors meet the requirements of 2D/3D plasma display panels (PDPs). In particular, under the excitation of vacuum ultraviolet (VUV) synchrotron radiation and ultraviolet (UV) irradiation, emission peaks corresponding to the ⁵D₃→⁷F_J (J=6, 5, 4, 3) and ⁵D₄→⁷F_J (J=6, 5, 4, 3) transitions of Tb³⁺ ions were recorded. Monitoring the ⁵D₄→⁷F₅ emission of Tb³⁺ at 545 nm, the excitation bands were assigned to the host-related absorption as well as the 4f–5d (fd) and the 4f–4f (ff) transitions of Tb³⁺. The produced phosphors can be efficiently excited at 147 nm, and have an adequately short decay time (τ_1/10=1.14 ms).     

Dynamic registration of D2 16O absorption spectrum in silica aerogel

Absorption spectra of the gas phase and adsorbed D₂О in the silica aerogel with nanoscale pores were investigated in 3700–5400 cm^?1 range using dynamic registration with Fourier Transform spectrometer IFS-125M. Two types of sample with pores of 60 nm wide – the nitrogen gas-treated and untreated aerogels – were examined. The surface treatment of the sample changes noticeably the broadband absorption of adsorbed water. Spectrum of D₂O in the pores differs from the spectrum of bulk water as for bandwidth so for band maximum. It was found that treatment of the pores by dry nitrogen leads to increasing hydrophilic properties of the material and to change water band contour. The D₂О line widths in both the aerogels exceed those of free monomer in 1.1–3 times at the same pressure. Calculations of self-broadening coefficients of the D₂O lines were performed using semi-empirical method based on the impact theory of broadening and includes the correction factors. The calculated results well agree with experimental data. Greater differences were found for the shift of the line centre. The D₂O line shifts in the treated pores significantly exceed line shifts in the untreated pores. For some lines, these shifts have the opposite sign indicating complex nature of the molecule–wall interaction.     

Intermolecular potential for Ar+D2O from differential cross sections

Differential cross sections for the scattering of D₂O (velocity selected beam) by Ar (nozzle beam) were measured at kinetic energies, ē, of 13·5 × 10^-14 erg? and 17·0 × 10^-14 erg by the crossed molecular beam technique. The distributions were compared with differential cross sections calculated from Lennard-Jones (12, 6) and Kihara-Stockmayer trial potentials to determine the potential parameters.     

Die Eigenschwingungen des Metall-Hydratkomplexes in BeSO4·4H2O und BeSO4·4D2O

Infrared reflection spectra of single crystals of BeSO₄·4H₂O and BeSO₄·4D₂O have been obtained in polarized light at 300°K and at 14°K in the region between 4000 cm^?1 and 300 cm^?1. By a Kronig-Kramers analysis, the frequencies of the infrared active transitions have been calculated. These transitions are attributed to internal vibrations of the water molecules and sulfate ions and, in the region between 1000 cm^?1 and 300 cm^?1, especially to internal and external vibrations of the tetrahedral Be⁺⁺·4aqu-complexes. The vibrational modes of these complexes consist of a superposition of translational and librational modes of the water molecules and translational modes of the central Be⁺⁺-ion. The vibrational frequencies and normal modes of this complex have been calculated in a central-force model, and force-constants have been determined by fitting the calculated frequencies to the observed spectra. The calculations have shown that the modes, which comprise mainly translational motions of the water molecules, are strongly coupled with librational motions of the water molecules. On the other hand, there exist pure librational modes with practically no admixture of translational motions. The optimum sets of force constants for the BeSO₄·4H₂O crystal and the BeSO₄·4D₂O crystal differ in a manner which can be understood under the assumption that the dimensions of the Be(D₂O)₄ complex are about 0.1 Å larger than those of the Be(H₂O)₄ complex. Some arguments supporting this conclusion will be discussed.