Die Reaktion von Arsenazo III mit H+, La3+, Sm3+, Gd3+, Dy3+ und Yb3+

Ohne Zusammenfassung     

The structure of the H3O+ hydronium ion in benzene

Infrared, X-ray structural, 1H NMR, and computational evidence for pi-solvation of H3O+ by benzene molecules is presented. A salt with a discrete [H3O.3benzene]+ cation can be isolated using a very weakly interacting carborane counterion, CHB11Cl11-. pi-Arene solvation of H3O+ explains the solubility of this salt in benzene solution. Similar results are indicated for the "Zundel-type" H5O2+ ion. These findings suggest structures for the active protonating species when strong acids are used as catalysts in arene solvents containing trace water. They are also relevant to structures that may be present in biological proton transport.     

Localized vibrations of H−Na+H− impurity in KCl crystal

Localized modes due to H^?Na⁺H^? complex impurity in KCl crystal have been computed by a Green function method and compared with experimental data.     

Energy surface calculations for the reaction HF + H+ ⇌ HFH+

Various GTO basis sets were investigated for their effectiveness in determining the SCF energy and geometry of the HFH⁺ molecule. A double zeta set augmented with a p_z function on each H atom was used to calculate the potential energy surface for the collinear protonation of HF. Limited configuration interaction calculations gave an energy of ?100.27365 E_a for an HF separation of 1.819 a₀ and a bond angle of 118.1°, and an energy of protonation of 119.5 kcal/mol.     

The electronic structure of CrO3+ and MoO3+ complexes

The results of ab initio molecular orbital calculations for [CrOf_s]^2? and polarised single crystal electronic spectra of [MoOCl₃(Op(NMe₂)₃)₂] and Ph₄As[MoOCl₄(H₂O)] are presented. These data are consistent with the electronic transitions of the MO³⁺ moieties, O_2pπ → M_dxy and M_dxy → Md_dxy,dyz being the lowest energy transitions in the spectra of their respective complexes, both these transitions being of low intensity.     

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.     

Spektralphotometrische Studie der Reaktionen von Methylnaphtholorange mit H+, Ti4+, Sm3+ und UO22+

Zusammenfassung Es wurde eine neue metallochrome Substanz, das 2-Bis(carboxymethyl)-aminomethyl-4(p-sulfophenyl)azo-naphthol synthetisiert, Methylnaphtholorange genannt. Ihre konsekutiven Dissoziationskonstanten wurden bestimmt, optimale Bedingungen ihrer Reaktion mit Ti⁴⁺, Sm³⁺ und UO ₂ ²⁺ aufgefunden, die Zusammensetzung der entstehenden Metallkomplexe festgestellt und die Bildungs- als auch Stabilitätskonstanten berechnet.

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Summary A new metallochromic compound, 2-Bis(carboxymethyl)-aminomethyl-4(p-sulphophenyl)-azonaphthol, (named methylnaphthol orange) has been synthezised. Its consecutive dissociation constants have been determined, optimal conditions of its reactions with Ti⁴⁺, Sm³⁺ and UO ₂ ²⁺ worked out, the composition of the metal complexes identified and the constants of formation and stability have been computed.

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Für technische Hilfe hei dieser Arbeit bin ich Herrn K. Haas dankbar.     

The lowest states of the O3+ ion

A CAS SCF calculation of the potential surfaces for the lowest states of the O₃⁺ ion is reported. An assignment of the bands in the HeI photoelectron spectrum is based upon calculated vibration profiles. This assignment shows the ground state of the ion to have ²B₂ symmetry. Also the weak bands at 15.6, 16.5 and 17.5 eV are reassigned.     

Diabatic potential energy surfaces of H+ + CO

Ab initio adiabatic and diabatic surfaces of the ground and the first excited electronic states have been computed for the H⁺ + CO system for the collinear (γ = 0°) and the perpendicular (γ = 90°) geometries employing the multi-reference configuration interaction method and Dunning’s cc-pVTZ basis set. Other properties such as mixing angle before coupling potential and before coupling matrix elements have also been obtained in order to provide an understanding of the coupling dynamics of inelastic and charge transfer process.     

A comparative study of H+ and Li+ interactions with oxygen bases

Ab initio SCF calculations have been performed to investigate the structural and electronic features of the interactions of H⁺ and Li⁺ with the oxygen bases H₂CO and OH^?. The data indicate that the OH interactions are primarily covalent while the LiO interactions are primarily electrostatic, although the LiO interaction in LiOH has considerable covalent character.     

The vibrational structure of NO+(X 1Σ+) from charge-exchange mass spectrometry

Charge-exchange mass spectrometry has been used to detect the first five vibrationl levels of the electronic ground-state ion NO^?(X ¹Σ^?). The absolute charge-exchange cross sections between thermal NO gas and 33 positive ions of 10 eV kinetic energy are given.     

The electronic structure of the [(NH3)5CoO2Co(NH3)5]5+ ion

SCCC MO calculations of the [(NH₃)₅CoO₂Co(NH₃)₅]⁵⁺ cation were carried out. On the basis of the results obtained, the magnetic properties and bond characters of the compound are discussed. Finally, the electronic structure of the O₂^? group as a ligand is analyzed.     

Zur elektrochromatographischen Trennung von Y3+, La3+, Ce3+, Pr3+ und Nd3+

Ohne Zusammenfassung     

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.     

The Ce3+ ion in strontium titanate (SrTiO3): Optical absorption and photoelectrochemistry

The presence ofCe³⁺(4f¹) in SrTiO₃ results in a broad optical absorption in the visible region. This is ascribed to a charge-transfer transition from Ce³⁺ to Ti⁴⁺. This material is not successful as an anode in photoelectrochemical cells. The reasons for this are discussed.     

A pios study of the reaction Ne(3P2,0) + HCl → Ne + HCl+ (A2Σ+) + e−

The HCl⁺ (A) vibrational state distributions from the title reaction were studied over the 48–110 meV collision energy range. The $\text{1}\text{0}$ and $\text{2}\text{0}$ ratios increase by factors of about 1.3 and 2.5, respectively. The branching ratios appear to be determined primarily by Franck-Condon factors, and by the endoergicity of the ν′ = 2 level.     

Magic cluster ion distributions: (NO)3+ (N2O)n and (NO)3+ (CO2)n

Supersonic jet expansions of mixtures of nitric oxide with either nitrous oxide or carbon dioxide have been investigated over a wide range of relative concentrations. Mixed molecular cluster ions of the form (NO) _m ⁺ (N₂O)_n and (NO) _m ⁺ (CO₂)_n are detected following non-resonant two-photon ionization. Over a wide range of intermediate concentrations, the cluster ion distributions (NO) ₃ ⁺ (N₂O)_n and (NO) ₃ ⁺ (CO₂)_n with n30 are significantly more intense than clusters containing other numbers of nitric oxide molecules. The extra abundance of these species is attributed to their especially stable structures and several possible forms are discussed. An intriguing possibility involves a stable cyclic nitric oxide trimer (or ion) when combined with nitrous oxide or carbon dioxide clusters.     

Discrimination between the permeation of H+ and OH− ions in precipitation membranes

The unique property of precipitation membranes, which allows determination of permeation rates of single ion species by measurement of current—voltage relationships, has been used to measure the transport rates of H⁺ and Oil ions. The permeation of OH^? was found to be approximately 4-5 times higher than that of H⁺ in both BaSO₄ and calcium oxalate precipitation membranes.     

Proton—molecule collisional interactions. I. The H+CO(1Σ) potential energy surface

Ab initio calculations are reported for the ground state potential energy surface (PES) of a CO molecule interacting with a proton, by treating the target as a rigid rotor and by performing accurate SCF computations over a wide range of relative distances and internal angles. The special nature of the forces at play in the short-range and intermediate range regions is discussed and protonated equilibrium geometries examined. An analytic fit of the various coefficients appearing in the well known multipolar expansion of the PES is also presented and the highly anisotropic form of this interaction is discussed. Vibrational effects are finally investigated by calculations at various r_CO values and their behaviour analysed in terms of simple stretching parameters.     

Sensitization of Tb3+ luminescence with Ce3+ in LaOBr: Tb3+, Ce3+

Luminescence emission and uv-excitation properties of LaOBr: Tb³⁺, LaOBr: Ce³⁺, and LaOBr: Tb³⁺, Ce³⁺ phosphors were studied. The visible emission spectra of La_0.995Tb_0.005OBr consists of⁵D_3,4 →⁷F_3–6 transitions in the wavelength range of 410–630 nm. The excitation of the Tb³⁺ ion gives a broad 4f → 5d transition band at 254 nm and weaker4f → 4f transition lines above 300 nm. The uv-excitation and emission of La_0.995Ce_0.005OBr at 290, 315, 355 (excitation), and 440 nm (emission) originate from transitions between the 4f-ground state and the four crystal field components of the5d²D excited state. The sensitization of Tb³⁺ luminescence in LaOBr with Ce³⁺ at varying concentrations is described and discussed. With increasing Ce³⁺ concentration the ⁵D₃ →⁷F transitions of Tb³⁺ quench totally and the⁵D₄ →⁷F transitions begin to quench gradually. The excitation spectrum of the⁵D₄ →⁷F₅ transition of Tb³⁺ consists of four bands due to Tb³⁺ and Ce³⁺, of which the three Ce³⁺ bands increase in intensity and the Tb³⁺ band decreases as the Ce³⁺ concentration is increased.