Coincidence studies of fluorescence and dissociation processes in electronic excited states of I2+, Br2+, IBr+ and ICl+

The PIFCO technique in which mass-selected photoion—fluorescence photon coincidences are counted, was used to investigate whether I₂⁺, IBr⁺ and ICl⁺ fluoresce. Measurements were made of lifetimes and fluorescence quantum yields of electronic excited states of these ions. Emission was discovered for I₂⁺ and IBr⁺, but ICl⁺ apparently does not fluoresce. Information on the radiative properties of Br₂⁺ was obtained as a by-product of the work on IBr⁺. Fragment ion kinetic energy releases were determined and provide information on dissociative ionization processes in the halogen and interhalogen ions studied.     

Energy disposal in thermal-energy charge-transfer reactions: Ar+,Kr+ and Xe+ with NH3

Thermal-energy charge-transfer reactions from the ²P_3/2 state of Ar⁺, Kr⁺ and Xe⁺ with NH₃ are shown to be non-energy resonant: the kinetic energy released in each case has been measured, and the internal energy of the NH⁺₃ product ions deduced. Possible quenching of ²P_1/2 state of rare-gas ions in ICR cells is discussed.     

Wavelength-resolved fluorescence lifetimes of gas-phase ions: CO2+ and CS2+

A method is described for measuring wavelength-resolved fluorescence lifetimes of ions formed by HeIα photoionization, using electric-field drift of the ions in competition with fluorescence. Fluorescence lifetimes of 216 and 232 ns for the 357 nm and 378 nm peaks of N₂O⁺, and 3.5 μs for the à → X? band of CS₂⁺, were measured. The wavelength-resolved à → X? band of CO₂⁺ showed no significant dependence of fluorescence lifetime on V′, but there is some indication of variation in the CS₂⁺ lifetimes in the à → X? band.     

Na+/K+-ATPase: Activity and inhibition

The aim of the study was to give an overview of the mechanism of inhibition of Na⁺/K⁺-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl₂DMSO₂], [AuCl₄]⁻, [PdCl₄]²⁻, [PdCl(dien)]⁺, [PdCl(Me₄dien)]⁺), transition metal ions (Cu²⁺, Zn²⁺, Fe²⁺, Co²⁺), and heavy metal ions (Hg²⁺, Pb²⁺, Cd²⁺) on the activity of Na⁺/K⁺-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed. The article is published in the original.     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.     

ESR spectra and magnetic constants of α-Al2O3:Co2+,H+ and α-Al2O3 :Co2+,X+

New anisotropic ESR spectra of Co²⁺ doped sapphire, different from hitherto known, are reported. The new spectra which are observed, beside the well-known spectra of α-Al₂O₃:Co²⁺, are shown to form two sets, each one consisting of six spectra (1–6) and (7–12). The spectra of both sets are proven to be interrelated by B_3a symmetry. g and A tensors for each set will be given. Evidence is given that the two sets are to be assigned to the defects α-Al₂O₃:Co²⁺,H⁺ and α-Al₂O₃:Co²⁺,X⁺. The former is concluded to consists of a Co²⁺ ion at the substitutional site (c) and a proton located in a potential minimum along a straight line between O^2- ions situated in O²⁺ triangles above and below the CO²⁺ ion. The potential function for the proton has been calculated by quantum-chemical calculations to clucidate the geometrical structure of the paramagnetic center. The α-Al₂O₃:Co²⁺,X⁺ could not be fully analyzed but some evidence is presented, that X⁺ might be alkali ions.     

Solvent extraction of H3O+, NH4+, Ag+, K+, Rb+ and Tl+ into nitrobenzene by using cesium dicarbollylcobaltate in the presence of a hexaarylbenzene-based receptor

From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium M⁺(aq) + 1·Cs⁺(nb) \rightleftarrows \rightleftarrows 1·M⁺(nb) + Cs⁺(aq) taking part in the two-phase water–nitrobenzene system (1 = hexaarylbenzene-based receptor; M⁺ = H₃O⁺, NH₄ ⁺, Ag⁺, K⁺, Rb⁺, Tl⁺; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML⁺ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the series of Rb⁺ < K⁺ < Ag⁺, Tl⁺ < H₃O⁺, NH₄ ⁺.     

Effect of Ar+, He+, and S+ Irradiation on n-InP Single Crystal

The irradiation effects of Ar⁺, He⁺, and S⁺ with energy from 10 eV to 180 eV on n-InP(100) surface are analyzed by X-ray photoelectron spectroscopy and low energy electron diffraction. After irradiation on the n-InP surface, damage on the surface, displacement of the Fermilevel and formation of sulfur species on S⁺ exposed surface are found and studied. Successive annealing is done to suppress the surface states introduced by S⁺ exposure. However, it is unsuccessful in removing the damage caused by noble ions. Besides, S⁺ ions can efficiently repair the Ar⁺ damaged surface, and finally form a fine 2×2 InP surface.     

Experimental determination of repulsive potentials between alkali ions (Li+, Na+, and K+) and N2 and CO molecules

Integral scattering cross sections have been measured for alkali ions (Li⁺, Na⁺ and K⁺) in the energy range 500–4000 eV scattered by room temperature N₂ and CO molecules through effective laboratory angles greater than 5 × 10^?3 rad. The repulsive potentials deduced from the cross sections are represented bya practically identical formula for the Na⁺N₂ and Na⁺CO systems, and for the K⁺CO systems, respectively, while the repulsive potentials of the Li⁺N₂ system are somewhat smaller than those of the Li⁺CO system at larger intermolecular distances.     

Rotational analysis of the a3Π0+,1-X1Σ+ emission systems of GeH+

New emission systems have been observed from the helium afterglow reaction of GeH₄ in the 520–610 nm region. On the basis of the rotational analysis, they were assigned to the a ³Π_0⁺-X¹Σ⁺ and a³Π₁-X¹Σ⁺ subsystems of GeH⁺. Spectroscopic constants have been determined for the GeH⁺ (a³Π_0⁺, a³Π₁, X¹Σ⁺) states.     

Chemical composition and crystal structure of β-alumina type R+-gallate (R+ = K+, NH+4)

The crystal structures of β-alumina type K⁺-gallate (K⁺-β-gallate), Mg²⁺-doped K⁺-β-gallate, and NH⁺₄-β-gallate were refined by the single crystal X-ray diffraction method. The positive charges of excess K⁺ ions in K⁺-β-gallate were compensated by O^2? ions in the mO site which coordinated with interstitial Ga³⁺ ions. The charge compensation mechanism mentioned above was changed by doping with Mg²⁺ ions. The excess charges in Mg²⁺-doped K⁺-β-gallate were compensated by the replacement of Mg²⁺ ions for Ga³⁺ ions at the middle of spinel block. No defects were found in NH⁺₄-β-gallate for the charge compensation, which was completely consistent with the result of thermal analysis that indicated a stoichiometric composition of NH⁺₄-β-gallate.     

Stability constants of the Li+, Na+, H3O+, NH4+, Ag+, and K+ complexes of the cone conformer of tetraethyl p-tert-butyltetrathiacalix[4]arene tetraacetate in nitrobenzene saturated with water

Abstract  

From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constants of the tetraethyl p-tert-butyltetrathiacalix[4]arene tetraacetate (cone)·M⁺ complexes (M⁺ = Li⁺, H₃O⁺, NH₄ ⁺, Ag⁺, or K⁺) were determined in water-saturated nitrobenzene. It was found that these constants increase in the cation order NH₄ ⁺ < K⁺ < H₃O⁺ < Ag⁺ < Li⁺ < Na⁺.     

Allowed transitions and the dipole moment of HD+

Within the Born-Oppenheimer approximation homopolar isotopically unsymmetric diatomic ions (HD⁺, ¹⁴N¹⁵N⁺, ³⁵Cl³⁷Cl⁺, etc.) have D_∞h symmetry and a non-vanishing dipole moment. This apparent paradox is reconciled here by treating carefully the transformation properties of the dipole moment operator in the D_∞h group.     

The properties of clusters in the gas phase: ammonia about Bi+, Rb+, and K+

Thermodynamic data are reported for NH₃ clustered about Bi⁺, Rb⁺, and K⁺ in the gas phase. Unusually strong bondings of NH₃ to Bi⁺ suggests the probable importance of partial covalent bonding in stabilizing the first ligand cluster. Differences in relative bond strengths for NH₃ and H₂O about Rb⁺ andK⁺ are consistent with the results of extended Hückel calculations reported herein.     

Product translational energy distributions and collision mechanics of the N + + CO reaction

Using a tandem mass spectrometer, kinetic energies of the five products CO ⁺, C ⁺, O ⁺, NO ⁺, CN ⁺ of reactive N ⁺ + CO collisions have been measured in the forward direction with respect to the N ⁺ beam. While CO ⁺ is observed mainly close to zero energy in the lab system, corresponding to formation by glancing collisions, there is evidence for formation of C ⁺ and O ⁺ via an intermediate NCO ⁺ complex at low impact energies. The productions of NO ⁺ and CN ⁺ show a very clear transition from complex to stripping reaction mechanism between 5 and 20 eV _lab. Highly excited NO ⁺ and CN ⁺ ions are formed up to impact energies of 60–70 eV _lab in the c.m. forward direction. In addition, these ions are formed in the backward c.m. direction up to very high collision energies (at least 200 eV _lab). This is explained by a collinear knock-on mechanism.     

Stability constants of complexes of Li+, H3O+, NH 4+ and Ag+ with hexaethyl calix[6]arene hexaacetate in nitrobenzene saturated with water

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺(aq)+NaL⁺(nb)⇔ML⁺(nb)+Na⁺(aq) taking place in the two-phase water-nitrobenzene system (M⁺ = Li⁺, H₃O⁺, NH₄⁺, Ag⁺; L = hexaethyl calix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the ML⁺ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order H₃O⁺<NH₄⁺<Li⁺<Ag⁺.     

Solubility and Ionic Processes in the Cu X 2? MX ?H2O ( X ?=Cl?, Br?; M +=Li+, Na+, K+, NH4+, Cs+) Systems

 Solubility isotherms in the CuBr₂−MBr−H₂O (M ⁺ = Li⁺, Na⁺, Cs⁺) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated solutions was performed.     

Ã2Σ+ → X̃+Π Emission spectra of the phosphaethyne cations,HCP+ and DCP+

The electron impact excited òΣ⁺ → X?⁺Π emission spectra of HCP⁺ and DCP⁺ have been observed. The spin-orbit split 0-0 band has maxima at 593.7 and 599.0 nm for HCP⁺ and 593.6 and 598.8 nm for DCP⁺. Short progressions in the V₃(CP) vibration are observed. a₀, v₃ and the upper-state lifetime are determined.     

Thermal-energy charge transfer of Ar+ with H2O: Internal and kinetic energy of the product H2O+

The reaction of Ar⁺ with H₂O has been investigated at near-thermal energy. The product ions H₂O⁺ and ArH⁺ account for 90 and 10% of the total reaction rate, respectively. Kinetic energy measurements and emission spectroscopy of the H₂O⁺ product ions are reported. It is concluded that at least 60% of H₂O⁺ ions are in the X? state with ≈2.4 eV vibrational energy while up to 40% are in the à state with a mean vibrational energy of 1.4 eV; the à state vibrational distribution has been determined. It is shown that both H₂O⁺ states are populated via an energetically “non-resonant” charge transfer process.     

Mobilities of H+3 and HeH+ ions in helium gas and rate coefficient for HeH+ + H2 → H+3 + He

The mobilities of mass-identified H⁺₃ and HeH⁺ ions in helium and the reaction rate coefficient for HeH⁺ + H₂ → H⁺₃ + He have been measured by a drift-tube quadrupole mass spectrometer at 300 K. The zero-field reduced mobilities of H⁺₃ and HeH⁺ ions, corrected to 273 K, are 31.0 ± 0.8 and 23.4 ± 0.6 cm² V^?1 s^?1 respectively. The reaction rate coefficient was found to be (1.26 + 0.16) × 10^?9 cm³s^?1 and was observed to be independent of the mean ion kinetic energy in the range from 0.04 to 0.3 eV.