Theoretical and experimental analysis of the fine structure and hyperfine structure in the configurations 5p6s and 5p6p of the antimony II spectrum

From 17 transitions in the singly ionized Sb II spectrum the hyperfine structure (A andB splitting constants) of the complete excited configurations 5p6s and 5p6p were determined by means of optical interference spectroscopy. In addition, a theoretical analysis both of the fine structure and also of the hyperfine structure was carried out (in the case of 5p6p of the general typenpn′p for the first time in literature). For the 3 levels 5p6p ³ P ₁, 5p7p ³ D ₂ and 5p6p ¹ P ₁ a different classification was found and consistent values for the fine structure parameters, mixing coefficients and single electron hyperfine structure splitting parametersa _nl ^ik andb _nl ^ik were obtained. The three new determinations in Sb II of the quadrupole moment (in barn) of¹²¹Sb (Q(5p6s)=?0.55(5);Q(5p6p)=?0.57(5) from the 5p-electron andQ(5p6p)=?0.7(2) from the 6p-electron) are well agreeing with each other but differ to former values from SbI. The core polarization and isotope shift of the lines, however, are compatible with our former results in SbI.     

On the system cerium-platinum-silicon

Phase relations in the ternary system Ce-Pt-Si have been established for the isothermal section at 800 °C based on X-ray powder diffraction, metallography, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) techniques on about 120 alloys, which were prepared by various methods employing arc-melting under argon or powder reaction sintering. Nineteen ternary compounds were observed. Atom order in the crystal structures of τ₁₈-Ce₅(Pt,Si)₄ (Pnma; a=0.77223(3) nm, b=1.53279(8) nm c=0.80054(5) nm), τ₃-Ce₂Pt₇Si₄ (Pnma; a=1.96335(8) nm, b=0.40361(4) nm, c=1.12240(6) nm) and τ₁₀-CePtSi₂ (Cmcm; a=0.42943(2) nm, b=1.67357(5) nm, c=0.42372(2) nm) was determined by direct methods from X-ray single-crystal CCD data and found to be isotypic with the Sm₅Ge₄-type, the Ce₂Pt₇Ge₄-type and the CeNiSi₂-type, respectively. Rietveld refinements established the atom arrangement in the structures of Pt₃Si (Pt₃Ge-type, C2/m, a=0.7724(2) nm, b=0.7767(2) nm, c=0.5390(2) nm, β=133.86(2)°), τ₁₆-Ce₃Pt₅Si (Ce₃Pd₅Si-type, Imma, a=0.74025(8) nm, b=1.2951(2) nm, c=0.7508(1) nm) and τ₁₇-Ce₃PtSi₃ (Ba₃Al₂Ge₂-type, Immm, a=0.41065(5) nm, b=0.43221(5) nm, c=1.8375(3) nm). Phase equilibria in Ce-Pt-Si are characterised by the absence of cerium solubility in platinum silicides. Cerium silicides and cerium platinides, however, dissolve significant amounts of the third component, whereby random substitution of the almost equally sized atom species platinum and silicon is reflected in extended homogeneous regions at constant Ce content such as for τ₁₃-Ce(Pt_xSi_1−x)₂, τ₆-Ce₂Pt_3+xSi_5−x or τ₇-CePt_2−xSi_2+x.     

Iridodials: enantiospecific synthesis and stereochemical assignment of the pheromone for the golden-eyed lacewing, Chrysopa oculata

1R,2S,5R,8R; 1R,2S,5R,8S; 1S,2S,5R,8R; and 1S,2S,5R,8S-Iridodials have been prepared in five steps from 4aS,7S,7aR and 4aS,7S,7aS-nepetalactones, major components of catnip oil. 1R,2S,5R,8R-Iridodial has been identified as a male-produced male-aggregation pheromone for Chrysopa oculata, the first pheromone of any kind identified for lacewings.     

An estimation of the temperature dependence of the excluded-volume integral

Lower critical solution temperatures (LCST) of trans-decalin solutions of polystyrene were measured on a newly built electric thermostat, the theta point Θ_L associated with the LCST being determined as 662 K. By use of this result together with the literature data for the ordinary theta point (Θ_U) and the entropy of dilution parameter, the excluded-volume integral B(T) was estimated in terms of the Eichinger method over the temperature range Θ_U to Θ_L. This enabled us to calculate the excluded-volume variable $\text{z}\text{as}\text{0.770 C}{}_{\mathrm{<mtext>M</mtext>}}\text{′ B(T)}\text{M}{}_{\mathrm{<mtext>w</mtext>}}{}^{0.5}$. Here, C_M′ is a numerical factor specific for a given polymer-solvent system and $\text{M}$_w is the weight-average molecular weight. Using the z values calculated from the above expression, we analysed the data on dilute solution properties of polystyrene reported by Berry and by Inagaki et al. It was found that the Domb-Barrett and the Suzuki equations for α_s (the linear expansion factor for the radius of gyration) were in good agreement with Berry's data of light scattering. The first coefficient k₁ in the series α_ν³ = 1 + k₁z + … (α_ν: the hydrodynamic expansion factor) was experimentally evaluated as 1.70. Furthermore, a conversion of the Suzuki equation for α₅ into that for α_ν with this k₁ value was found to account quite satisfactorily for the viscosity behaviour observed by Inagaki et al.     

Calculation of the rotational magnetic moments of the ammonia and water molecules

We calculate the rotational magnetic moments and the corresponding g-factors for water and ammonia. Our results are g_xx = 0.397, g_yy = 0.769 and _zz = 0.345 for water and g_xx = g_yy = 0.69 and g_zz = 0.51 for ammonia. The experimental values are g_xx = 0.585, g_yy = 0.742 and g_zz = 0.666 for water and g_xx = g_yy = 0.56 and g_zz = 0.484 for ammonia.     

Stereoselective synthesis of the both enantiomers of disparlure,the pheromone of the gypsy moth

The both enantiomers of disparlure [(7R, 8S)-(+)-epoxy-2-methyloctadecane and its (7S,8R)-(?)-isomer] were synthesized from (2R, 3R)-(+)-tartaric acid in a stereoselective manner. (+)-Disparlure was found to be biologically active.     

Determination of the population,depopulation and the anisotropic spin lattice relaxation rates in the photoexcited triplet state of phenazine. A light modulation-EPR study

The photoexcited triplet state of phenazine in toluene glasses at 35 K is investigated by light modulation-EPR spectroscopy. From the transient EPR spectra and the kinetics in the three canonical orientations (p = x, y, z) the rate parameters are determined. Thus, the depopulation rate constants k_p, the anisotropic spin lattice relaxation rate constants W_p, and the ratios between the population constants A_p are calculated: k_x = (2.2 ± 0.3) × 10² s^?1, k_y = (0.21 ± 0.04) × 10² s^?1, k_z = (0.06 ± 0.03) × 10² s^?1, W_x = (8.6 ± 0.9) × 10³ s^?1, W_y = (11.0 ± 1.0) × 10³ s^?1, W_z = (14.0 ± 1.4) × 10³ s^?1, and A_x: _Ay:A_z ≈ 1:0.04:0.02. It is concluded therefore that the in-plane spin state |τ_x > is the active one.     

On the partial reversibility of the Β-lactoglobulin heat denaturation

The thermal behavior ofΒ-lactoglobulin (Β-lg) disperesed in distilled water (pH=3.2) is studied dy differential scanning calorimetry (DSC) in the temperature range 20?C–120?C and within a concentration region of 3.5% to 24%. Recently [1] we have determined by DSC the kinetic parameters for the heat-denaturation ofΒ-lg. The effect of the protein concentration and of the thermal treatment on transition temperature (T _trs), half-widths of the peak (δT _1/2), of apparent enthalpy changes (δ_app H) and of Van't Hoff enthalpies (δ_VH H) have been examined for the concentrations of 8.8% and 24%. In this study we have undertaken complementary experiments for the concentrations 3.5% and 10.8%. The half-widths of the peaks, which depend on the cooperativity of the denaturation process [2], decrease with increasing concentration. The ratio δ_app H/δ_VH H tends to 1, with low values of the protein concentration and with high scanning rates. This implies the hypothesis of a reversible step for the denaturation process ofΒ-lg.     

The kerr effect in the vicinity of the transition from the isotropic to smectic a phase

The equilibrium electrooptical effect in the isotropic phase of seven liquid crystalline substances (4-n-decyloxy-4′-cyanobiphenyl, carbosilane dendrimer of the fourth generation with cyanobiphenyl terminal fragments, and the fourth, fifth, sixth, seventh, and tenth members of the homologous series of 4-n-acylphenylene 4′-n-alkoxybenzoates) was studied. The smectic A phases were found to exhibit weaker divergence of the Kerr constant in the vicinity of the T _c isotropic melt-liquid crystal phase transition temperature compared with the nematic phases. The difference between T _c and the temperature T* of the virtual second-order phase transition varied from 3.2 to 19.0 K for the smectic A phases, which substantially exceeded the value (T _c-T*) ≤ 1 K for the nematic phases. A theory of the electrooptical properties of isotropic melts in the vicinity of the T _c temperature of the phase transition from the isotropic to smectic A phase is developed. An equation relating the T _c-T* difference to the phenomenological coefficients of the expansion of the Helmholtz energy of an isotropic melt into a series in powers of the coordination and orientational order parameters is obtained.     

Structural characterization of the Ta-rich part of the Ta-Al system

The Ta-rich part of the Ta-Al system has been investigated. On the one hand, the accommodation of the non-stoichiometry in the σ phase has been studied by Rietveld refinement of X-ray powder data obtained from different samples on both sides of the ideal composition (Ta₂Al, P4₂/mnm, tP30). On the other hand, the structure of the β phase has been determined ab initio from powder synchrotron data (analyzed composition Ta_50.7Al_49.3, refined composition Ta_52.6(5)Al_47.4(5) (Ta_45.2(4)Al_40.8(4)), stoichiometric composition Ta₄₈Al₃₈, mP86, P2₁/c, a=9.8707(1) Å, b=9.8766(1) Å, c=16.3539(2), β=116.478(1), R_B=2.6%). This phase is shown to be closely related to the group of the topologically close packed phases. In addition, phase relations have been accurately determined in the Ta-rich end of the system.     

Microcalorimetry study on the microbial activity of permafrost on the Tibetan plateau of China

Microcalorimetric techniques had been used to study the influence of different physicochemical parameters on microbial growth in different permafrosts on the Tibetan plateau. The total heat evolution of the permafrost samples amended with glucose, Q _T , the values of microbial growth rate constant, k, and the heat output power, P _t , were calculated from the power–time (P–t) curves. It is observed that the same coverage vegetation show similar P–t curves, which strongly suggest that the permafrost microorganisms of the homology vegetation coverage have similar structures of community. Furthermore, the vegetation degradation turns out to have significant influence, that is, the better the status of vegetation is, the higher the values of k, CFU and Q _T are.     

Fine structure and hyperfine structure in the excited configuration 5p 26s of the antimony I spectrum

By optical interference and VUV spectroscopy the doublet system of SbI 5p ²6s was investigated, so that now the hyperfinestructure of all 8 levels of 5p ²6s (A- andB-splitting constants) are known. From the analysis we receive a spin-orbit parameter ζ_5p =3,538(57) cm^?1 and from the hyperfine-analysis single electron splitting constantsa _5p ⁰¹ =52.4(4.6),a _5p ¹⁰ =?1.6(7.3),a _5p ¹² =72.3(2.3),a _6s ¹⁰ =91.7(4.1),b _5p ⁰² =?49.6(1.1) andb _5p ¹¹ =30.4(3.2) (all values in mK). For all calculations in the fs- and hfs-analysis the 5p ²6s ² D _3/2 has to be excluded (see discussion). With the figures given above the quadrupole moment¹²¹ Q(5p ²6s)=?0.44(3) barn was obtained. It is in good agreement with the¹²¹ Q(5p ³). For the core-polarization by the 5p electron in the innerfieldns-shells (n=1, 2, 3, 4, 5) and the unpaired 6s electron a field of +500(300) kG was obtained.     

Studies on the nongrowth metabolism of the different strains of Tetrahymena cells by isothermal microcalorimetry

The nongrowth metabolic processes of Tetrahymena strains with the different cell densities were monitored by isothermal microcalorimetry, including Tetrahymena thermophila BF₁, Tetrahymena thermophila SB210, Tetrahymena pyriformis GL, the mixed cells of T. thermophila BF₁ and T. thermophila SB210, and the mixed cells of T. thermophila BF₁ and T. pyriformis GL. All the typical power–time curves showed a decreasing trend on the whole. It was found that total heat production (Q _t) and maximum heat output (P _m) decreased significantly with the decrease of cell density. Cell density did not influence significantly the maximum heat output per cell (P _cell) of Tetrahymena cells, which was probably due to enough oxygen. The P _cell and metabolic decrease rate constant (K) values for the mixture of T. thermophila BF₁ and T. pyriformis GL, and that of T. thermophila BF₁ and T. thermophila SB210 were similar to the mean values of P _cell and K for the corresponding single Tetrahymena strain, respectively. It was speculated that the cell mixing did not possibly influence significantly their P _cell and K values because of no competition for nutrition, oxygen, and room, and the low conjunction percentages.     

Synthesis of the ABC-ring models of goniodomin A: preference for the unnatural configuration at C11 of the BC-ring in a non-macrocyclic model system

To confirm the natural relative stereochemistry of the ABC-ring of goniodomin A (1), the corresponding three stereoisomeric compounds, (2R,5S,6S,7S,9S,11R,15S)-, (2R,5S,6S,7R,9R,11S,15R)-, and (2R,5S,6S,7R,9R,11R,15S)-isomers (2, 3, and 5, respectively), were stereoselectively synthesized using a Nozaki-Hiyama-Kishi reaction as a key step. It was also found that a (2R,5S,6S,7R,9R,11S,15S)-isomer (4), corresponding to the absolute configuration of 1 recently proposed by Sasaki, was not detected during the formation of 5 from a common ketodiol substrate under acid-catalyzed spiroacetalization conditions. This would be attributable to the absence of a macrocyclic framework.     

A method for the calculation of heats of solution (ΔH s ) for organic compounds from the number of constituent carbon atoms and the functional groups

The heat of solution (ΔH _s ) of several homologous series of linear and monofunctional organic compounds (n-alkanes,n-alcohols,n-aldehyds and esters) in polar stationary phase (Carbowax 1540) can be expressed by ΔH _s =a+b·n _R +c·C _G , wherea is a constant,n _R is the number of carbon atoms not belonging to the functional group in the molecule andC _G represents the contribution of each functional group to the ΔH _s value. The accuracy of the ΔH _s values calculated by this equation is sufficient for all the compounds tested (average relative error=1.92%).C _G can be calculated from the plots ΔH _s versusn _R .     

The dependence of the magnitude of the spontaneous polarization on the cell thickness in ferroelectric liquid crystals

The magnitude of the spontaneous polarization (P) was measured for S-3,7-dimethyloctyl 4-n-hexadecyloxybenzoyloxybenzoate, a material with an isotropic to smectic C phase transition (T_c), using a triangular wave method. The temperature dependence of the measured values was well represented by the expression P = P₀(T_c-T)^α· P₀ was found to depend on the cell thickness for thicknesses below 18 μm, but saturated to a constant value above this limit. The value of the exponent α, on the other hand, was found to be insensitive to the cell thickness. The decreased value of the polarization in the thin cells is thought to be a result of polarization screening due to ionic impurities.     

478—Theory of Brdička current and the dependence of the current on cobalt ion concentration

An equation of Brdi?ka current and its experimental verification are presented, in which Brdi?ka current is expressed by a function of the surface concentration of protein, the bulk concentration of cobalt ion and two parameters, n_ck_c and k_f/k_d, characterizing the protein-zero-valent cobalt complex which is to catalize the hydrogen evolution, where n_c is the total number of sites on which the complex can be formed in a protein molecule, and k_c and k_d are the (average) constants representing the intrinsic catalytic activity and the lifetime respectively, of the complex.     

Homogeneity range of the NaTl-type Zintl phase in the ternary system Li-In-Ag

The remarkably broad homogeneity range of the NaTl-type Zintl phase in the ternary phase diagram Li-In-Ag at room temperature was determined by structure evaluation using X-ray powder diffraction. The colours of the investigated Zintl phases correlate with the valence electron concentration (VEC) as already established for the quasibinary cut Li_0.5(In_xAg_1−x)_0.5 with 0.47?x?1.00, i.e. with decreasing VECs the colour changes from grey over reddish to bright yellow. All compounds in the new quasibinary cut Li_x(In_0.5Ag_0.5)_1−x with 0.47?x?0.60 appear free from vacancies in the Li-sublattice, even for Li-deficient compositions. The partial occupation of Li-sites by excess Ag and In instead is in full agreement with the behaviour of the binary NaTl-type Zintl phases Li_xZn_1−x and Li_xCd_1−x (0.47?x?0.54) with a low VEC about 1.5.