Hyperfine structure and isotope shift of some even parity levels in the YbI spectrum

Using laser induced fluorescence spectroscopy the hyperfine structure of the even parity levels 4f ¹⁴6s6d ³ D ₁, 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 as well as of the odd parity level 4f ¹⁴ 6s6p ³ P ₂ in neutral ytterbium has been investigated. The isotope shift of the transitions 4f ¹⁴6s6p ³ P ₀ → 4f ¹⁴ 6s6p ³ D ₁ and 4f ¹⁴ 6s6p ³ P ₂ → 4f ¹⁴ 6s8s ³ S ₁, 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 could be measured with high accuracy. The results for the 4f ¹⁴ 6s6p ³ D ₁ level show a considerable influence of second order effects of the hyperfine interaction. The isotope shifts of the 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1 levels indicate a possible configuration mixing for these levels.     

Synthesis and properties of S,R-alternating octinaphthalenes

(S,R,S,R,S,R,S)- and (S,R,S,S,S,R,S)-octinaphthalenes were synthesized by oxidative coupling of (S,R,S)-quaternaphthalene, and differences due to axis chirality of (S,R,S,R,S,R,S)-, (S,R,S,S,S,R,S)-, (S,S,S,R,S,S,S)-, and (S,S,S,S,S,S,S)-octinaphthalenes were compared using the R_f values on TLC, specific optical rotations, ¹H NMR chemical shifts of the hydroxy groups, and CD spectra. A clear CD additivity was found in the Δ? values of the ¹L_a transition around 290 nm, which are proportional to the difference between the numbers of S and R binaphthalene units.     

Excess molar quantities of (a halogenated n-alkane + an n-alkane) A comparative study of mixtures containing either 1-chlorobutane or 1,4-dichlorobutane

Excess molar volumes V_m^E at 298.15 K were obtained, as a function of mole fraction x, for series I: {x1-C₄H₉Cl + (1 ? x)n-C_lH_{2l + 2}}, and II: {x1,4-C₄H₈Cl₂ + (1 ? x)n-C_lH_{2l + 2}}, for l = 7, 10, and 14. 10, and 14. The instrument used was a vibrating-tube densimeter. For the same mixtures at the same temperature, a Picker flow calorimeter was used to measure excess molar heat capacities C_{p, m}^E at constant pressure. V_m^E is positive for all mixtures in series I: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.277 for l = 7, 0.388 for l = 10, and 0.411 for l = 14. For series II, V_m^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆} is small and S-shaped, the maximum being situated at x_max = 0.178 with V_m^E(x_max)/(cm³ · mvl^?1) = 0.095, and the minimum is at x_min = 0.772 with V_m^E(x_min)/(cm³ · mol^?1) = ?0.087. The excess volumes of the other mixtures are all positive and fairly large: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.458 for l = 10, and 0.771 for l = 14. The C_{p, m}^Es of series I are all negative and |C_{p, m}^E| increases with increasing l: at x = 0.5, C_{p, m}^E/(J · K^?1 · mol^?1) is ?0.56 for l = 7, ?1.39 for l = 10, and ?3.12 for l = 14. Two minima are observed for C_{p, m}^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆}. The more prominent minimum is situated at x′_min = 0.184 with C_{p, m}^E(x′_min)/(J · K^?1 · mol^?1) = ?0.62, and the less prominent at x″_min = 0.703 with C_{p, m}^E(x″_min)/(J · K^?1 · mol^?1) = ?0.29. Each of the remaining two mixtures (l = 10 and 14) has a pronounced minimum at low mole fraction (x_min = 0.222 and 0.312, respectively) and a broad shoulder around x = 0.7.     

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.     

Conversion-time curves in the diffusion-controlled free radical polymerization of styrene

In order to calculate conversion-time curve in radical polymerization, the termination rate constant for interacting polymer radicals with chain lengths n and s is written as: k_t,ns = k(ζ_n + ζ_s) where k ∝ exp(−0.40/v_f) (v_f: free volume), and ζ = 1 at n ⩽ n_c and ζ = (n_c/n)^1,5 at n ⩾ n_c + 1 (n_c: a critical chain length of polymer moving by reptation). The curves are applicable to the experimental data obtained from 20°C to 154°C in the thermal polymerization of styrene. Further, it is shown that the curves can be applied to the experimental data for polymerization in the presence of initiator.     

Ultrasonic speed in compressed liquid by a sing-around method

A new apparatus for the measurement of ultrasonic speed in compressed liquid was constructed. The reliability of this instrument was confirmed by measuring the speeds in pure benzene in the ranges from 283.15 to 323.15 K and pressures up to near freezing pressure, and by comparing the results with literature values. The isentropic compressibilities κ_S were also determined using the experimental speeds and densities, and the results κ_S(u) were compared with those observed directly elsewhere κ_S(d) and those calculated thermodynamically κ_S(c) from (p, V_m, T). At atmospheric pressure, the present results, while agreeing with κ_S(u) reported in the literature, show differences from κ_S(d) and κ_S(c), while those for higher pressures close on a simple curve with κ_S(c).     

Thermodynamics for ionization of water at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa: apparent molar volumes of aqueous KCl,KOH, and NaOH and apparent molar heat capacities of aqueous HCl,KCl, KOH,and NaOH

Apparent molar volumes V_φof aqueous KCl, KOH, and NaOH and apparent molar heat capacities C_{p, φ}of aqueous HCl, KCl, KOH, and NaOH have been determined at the pressure p =  0.35 MPa, and at molalities 0.015 ⩽m / mol · kg ^− 1⩽ 0.5. Densities were measured using a vibrating-tube densimeter (DMA 512, Anton Paar, Austria) at temperatures 278.15 ⩽T / K⩽ 368.15. These values were used to calculate the apparent molar volumes. A fixed-cell, differential-output, power-compensating, temperature-scanning calorimeter (NanoDSC model 6100, Calorimetry Sciences Corporation, Spanish Fork, UT, U.S.A.) was used to measure the heat capacities of the same solutions at temperatures 278.15 ⩽T / K⩽ 393.15. Results were fitted by using equations that describe the surfaces (m, T, V_φ) and (m, T, C_{p, φ}). Using these equations, we have calculated the surfaces (m, T, Δ_rV_m), (m, T, Δ_rC_{p, m}), (m, T, Δ_rH_m), (m,T , p Q_a), and (m, T,Δ_rS_m ) for the ionization of water in the presence of combinations of the above electrolytes. The last three surfaces were calculated by integration using our (m,T , Δ_rC_{p, m}) surface and literature values for the molality dependence of Δ_rH_mand pQ_a at T =  298.15 K.     

Thermodynamics of proton dissociations from aqueous l-proline: apparent molar volumes and apparent molar heat capacities of the protonated cationic,zwitterionic, and deprotonated anionic forms at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa

Apparent molar volumes V_φ and apparent molar heat capacities C_p,φ were determined for aqueous solutions of l-proline, l-proline with equimolal HCl, and l-proline with equimolal NaOH at the pressure p=0.35 MPa. Density measurements obtained with a vibrating-tube densimeter at temperatures (278.15⩽T/K⩽368.15) were used to calculate V_φ values, and heat capacity measurements obtained with a twin fixed-cell, differential-output, power-compensation, temperature-scanning calorimeter at temperatures (278.15⩽T/K⩽393.15) were used to calculate C_p,φ values. Speciation arising from equilibrium was accounted for using Young’s Rule, and semi-empirical equations describing (V_φ, m, T) and (C_p,φ, m, T) for each aqueous equilibrium species were fitted by regression to the experimental results. From these equations, the volume change Δ_rV_m and heat capacity change Δ_rC_p,m for the protonation and deprotonation reactions were calculated. Additionally, the Δ_rC_p,m expression was integrated symbolically to yield values of the reaction enthalpy change Δ_rH_m, reaction entropy change Δ_rS_m, and equilibrium molality reaction quotient Q for both reactions. The results provide a much-improved thermodynamic characterization of aqueous l-proline and of its protonation and deprotonation equilibria.     

Semiclassical variational study of size effects in neutral and charged jellium droplets

An analytic expression for the total energy of metallic clusters composed ofN identical atoms of valencev and with net chargeQ is obtained by means of a variational solution of the Thomas-Fermi-Weizsäcker energy density functional within the spherical jellium model. The minimum energy is given as an expansion in decreasing powers of the cluster radiusR=r _s Z ^1/3, withZ=vN andr _s the radius per electron of the bulk metal. The coefficients are obtained as functions ofr _s . Terms of volume (R ³), surface (R ²), curvature (R), constant (R ⁰), (1/R) and (1/R ²) are clearly separated in the formula, as well as the different contributions (kinetic, coulombic and exchange-correlation) to each of them. The asymptotic values (R→∞) for the work functions,W(r _s ), and surface energies σ(r _s ), are compared to analogous semiclassical and Kohn-Sham calculations of jellium-like surfaces and to the experimental values. The size dependent behaviour of chemical potentials, μ(R), electron affinities,AF(R), and ionization potentials,IP(R), are easily obtained for any kind of metallic clusters. In particular we discuss the Coulomb and quantum corrections to the coefficients β, δ in the asymptotic formulae:IP?W+β/R andAF?W+δ/R.     

Apparent molar volumes and apparent molar heat capacities of aqueous potassium hydrogen phthalate (KHP) and potassium sodium phthalate (KNaP) at temperatures fromT = 278.15 K toT = 393.15 K at the pressure 0.35 MPa

A vibrating-tube densimeter (DMA 512P, Anton Paar, Austria) was used to investigate the densities and volumetric properties of aqueous potassium hydrogen phthalate (KHP) and potassium sodium phthalate (KNaP). Measurements were made at molalities m from (0.006 to 0.66)mol · kg ^− 1, at temperatures from 278.15 K to 368.15 K and at the pressure 0.35 MPa. The densimeter was calibrated through measurements on pure water and on 1.0 mol · kg ^− 1NaCl(aq). We also used a twin fixed-cell, power-compensation, differential-output, temperature-scanning calorimeter (NanoDSC 6100, Calorimetry Sciences Corporation, Spanish Fork, UT, U.S.A.) to measure solution heat capacities. This was accomplished by scanning temperature and comparing the heat capacities of the unknown solutions to the heat capacity of water. Apparent molar volumes V_φand apparent molar heat capacities C_{p, φ}of the solutions were calculated and fit by regression to equations that describe the surfaces (V_φ, T, m) and (C_{p, φ}, T, m). Standard state partial molar volumesV₂^o and heat capacities C_p,2^owere estimated by extrapolation to the m =  0 plane of the fitted surfaces. Previously determinedC_{p, φ} for HCl(aq) and NaCl(aq) were used to obtain (Δ_rC_{p, m}, T, m) for the proton dissociation reaction of aqueous hydrogen phthalate. This (Δ_rC_p,m, T, m) surface was created by subtracting C_p,φfor KHP(aq) and for NaCl(aq) from the sum of C_p,φfor KNaP(aq) and for HCl(aq). Surfaces representing (Δ_rH_m, T, m) and (pQ_a, T, m), where pQ_adenotes the molality equilibrium quotient, were created by integration of our (Δ_rC_p,m, T, m) surface using values for (Δ_rH_m, m) and (pK_a, m) at T =  308.15 K from the literature as integration constants.     

Numerical method of non-isothermal curve analysis by means of electrical resistance measurement during cooling

The temperature-dependence of the electrical resistance of Al-Zn 78 wt.% was measured during linear cooling of the samples in the range of eutectoidal decomposition. The resulting resistancevs. temperature curves were analysed by:

deriving the temperature-dependence of the volume fractionx(T) of theη precipitate;

fitting the theoretical functionx(T)=x _h (T)+x _c (T) following from numerical integration of the reaction rate equations for the simultaneously occurring homogeneous (H) and cellular (C) precipitation processes.

As a result, the activation energiesE _h andE _c , the JMA exponentsn _h andn _c , the rate constantsk _h andk _c , and the critical temperaturesT _o of the two processes were estimated.     

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.     

Molecular Zeeman effect of 3-oxetanone and 3-methylene oxetane,and the comparison of the magnetic-susceptibility anisotropies,molecular quadrupole moments,and other magnetic parameters with other four-membered rings

The molecular Zeeman effect is reported for 3-oxetanone and 3-methylene oxetane at fields near 20000 G. The results for 3-oxetanone are molecular g-values: g_aa = ?0.1059 ± 0.0008, g_bb = ?0.0581 ± 0.0004,g_cc = ?0.0437 ± 0.0004, magnetic susceptibility anisotropies:2x_aa -x_bb - x_cc = (9.6±0.5) x 10^?6 erg/G²mole, 2x_bb - x_aa - x_cc = ?(7.8±0.6) x 10^?6 erg/G²mole, and molecular quadrupole moments: Q_aa = ?(12.8±0.8) x 10^?26 esu cm,Q_bb = (7.9±0.8) x 10^?26 esu cm, and Q_cc = (4.9±0.8) x 10^?26 esu cm. For 3-methylene oxetane, the results are g_aa = ?0.0510 ± 0.0018, g_bb = ?0.0435 ± 0.0010, g_cc = ?0.0313 ± 0.0010, 2x_aa - x_bb - x_cc = ?(10.9±0.5) x 10^?6 erg/G² mole, 2x_bb - x_aa - x_cc = (2.3±0.9) x 10^?6 erg/G² mole, Q_aa = -?5.4±1.0) x 10^?26 esu cm, Q_bb = (5.1 ± 1.2) x 10^?26 esu cm, and Q_cc = (0.2±1.5) x 10^?26 esu cm. The bulk magnetic susceptibility for 3-oxetanone was measured to be x = 1/2 (x_aa+x_bb+x_cc) = ?(30.6±1.5) x 10^?6 erg/G² mole. The out-of-plane minus average in-plane magnetic-susceptibility anisotropies in four-membered rings show larger paramagnetism than predicted on the basis of localized group susceptibility anisotropies. This effect is discussed and a possible explanation presented.     

Calixarene coated gold nanoparticles as a novel therapeutic agent

In the current study, gold nanoparticles (AuC6NPs and AuC8NPs) were prepared through sodium borohydride reduction method by using Calix[6]rene and Calix[8]rene as a stabilizing agents. The synthesized AuNPs were screened for cytotoxic, phytotoxic, antifungal and antibacterial activities. The fabricated AuNPs were characterized by UV–visible spectroscopy, atomic force microscopy (AFM) and FTIR spectroscopy. Antibacterial activities of the AuNPs were tested against E. coli and S. aureus. The AuC6NPs were found to be effective against the growth of gram positive bacteria and inhibited the growth of S. aureus. AuC6NPs interact with bacterial cell and damaged cell membrane. Roughness of the bacterial surface and membrane rupture can be clearly observed by AFM images. The AuNPs possess insignificant antifungal activity against Aspergillus niger and Candida albicans. Moreover, AuC8NPs have significant phytotoxicity and moderate cytotoxicity.     

J and term dependences in the isotope shift of Eu I

High-resolution laser atomic beam spectroscopy has been applied to studyJ and term dependences in the isotope shift of the levels 4f ⁷5d6s a ¹⁰ D _J ,a ⁸ D _J of Eu I. A parametric analysis of the isotope shift has been performed. TheJ dependence is interpreted through two term-dependent parametersz _5d , and the term dependence through one parameterΔT:z _5d (a ¹⁰ D)=44.1 (2.6) MHz,z _5d (a ⁸ D)=55.9 (2.3) MHz,ΔT=408.5 (3.2) MHz. Ab initio Hartree-Fock and Dirac-Fock calculations have been made to interpret these parameters. Within the accuracy of the calculations the parameters can be attributed to field shift effects.     

Generalized quantum mechanical two-centre problems

If χ _i (χ _k ) is an exact generalized diatomic orbital (solution of Eq. (1) of text), a sequence of functions χ _i ^(N) converging to χ _i may be constructed so that matrix elements of frequently occurring operators between χ _i ^(N) and χ _k ^(N) may be computed without any numerical integration. Exact expectation values are given for kinetic and potential energy, dipole moment, θ ²=x ²+y ², and quadrupole moment 3z ²?r ², for various ratios of nuclear charges Z ₁,Z ₂ and for several distances R. Special subjects discussed in terms of computed expectation values are:

1. R-dependence of the contributions to total energy of HeH²⁺ in state 2pσ and of LiH³⁺ in state 3dσ
2. RZ-and λ-dependence of dipole and quadrupole moment functions in state 1sσ
3. Some properties of those generalized diatomic orbitals which approach, for R going to 0, Slater-type atomic functions.

     

Hyperfine structure in the configurations4f 4 6s 2 and4f 4 5d 6s of Nd I

The high resolution laser-atomic-beam technique was used to investigate the hyperfine structure in Nd I 4f ⁴6s ^{2 5} I,⁵ F,⁵ S and 4f ⁴5d6s ⁷ L,⁷ K,⁷ I,⁷ H. The metastable states were populated by an arc discharge burning in the atomic beam. The measured hyperfine constantsA andB of the levels of 4f ⁴6s ² and 4f ⁴5d6s allow a parametric analysis to be performed using the effective tensor operator formalism. The experimental radial integrals of the 4f and 5d electrons fit with those of the other lanthanides. The 4f radial integrals are in agreement with values of optimized Hartree-Fock-Slater calculations. The spectroscopic quadrupole moments of¹⁴³Nd and¹⁴⁵Nd are deduced from the 4f parameters:Q _I =?0.610(21) b and ?0.314(12) b, respectively. TheQ _I resulting from the 5d parameter are in satisfactory agreement with these values. The hyperfine anomaly due to thes electron in 4f ⁴5d 6s amounts to about 1%.     

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.     

Hyperfine structure in 5s 4d 3 D —5snf transitions of87Sr

The hyperfine spectra of the 5s4d ³ D ₁-5s20f, 5s4d ³ D ₂-5s23f, and 5s 4d ³ D ₃-5s32f transitions of⁸⁷Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction terma _5s and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d ³ D configurations, including theA- andB-factors and a separation of the individuals- andd-electron contributions to these factors, are derived.