Assignment of submillimeter laser lines in CH3I

We propose explanations for three laser lines observed in CH₃I by Dyubko, Svich and Fesenko. Two lines are respectively assigned to (J = 16, K = 6) → (J = 15, K = 6) and (J = 45, K = 6) → (J = 44, K = 6) in the ν₆ = 1 state. Th e third one might be explained as (ν₃ = 2, J = 54, K) → (ν₃ = 2, J = 53, K).     

Investigation of hyperfine structure and isotope shift of the 605.5 nm-line of Lu176 by laser spectroscopy

Using a tunable single mode dye laser the hyperfine structure of the transition 5d6s ^{2 2} D _5/2 — 5d6s6p ⁴ F _5/2 has been investigated for the Lu-isotopes Lu¹⁷⁵ and Lu¹⁷⁶. From our measurements the following values for the hyperfine constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _5/2:A=698.4 (0.4) MHz,B=1,564 (10) MHz 5d6s ^{2 2} D _5/2:A=104.1 (0.3) MHz.B=2,631 (6) MHz Lu¹⁷⁵ 5d6s6p ⁴ F ^5/2:A=987.2(0.4) MHz,B=1,117(6) MHz. The isotope shift between the line centers has been determined to be IS(176-175, 605.5 nm)=?420(10) MHz.     

Lifetimes of some highly excited levels in the Pb-I spectrum measured by the hanle method

Natural lifetimes of some highly excited levels in the Pb-I spectrum have been measured by the zero field level crossing (Hanle) method. The levels were reached by optical excitation from the metastable 6p ^{2 3} P ₂ and 6p ^{2 3} P ₁ states, were a considerable population had been created by means of adc discharge in a Pb atomic beam. An atomic beam source producing atoms in metastable states is described. For the lifetimes τ of the investigated levels we find:τ(6p(1/2)6d ³ D ₁)=3.74(28) ns,τ(6p(1/2)6d ³ F ₂)=25.8(1.3) ns,τ(6p(1/2)6d ³ D ₂)=4.17_(?31) ^(?49) ns,τ(6p(1/2)6d ³ F ₃)=6.08(26) ns,τ(6p(3/2)7s)³ P ₂=5.85(27) ns. These results are compared with lifetimes derived from oscillator strengths given in the literature.     

The physical ladders and relativistic generalizations

The research on the relativization of the hadron classification scheme, connected with the U(6, 6)-ladders is continued (this research has begun in [4]). For this purpose the semidirect product U(6, 6) · T(143) and its Lea algebra are used. A representation of U(6, 6) · T(143) is built with its help the generalized momenta and the generalized angular momenta are introduced. By means of their combinations with the ladder momenta a representation of the mentioned algebra is built; this representation namely gives a possibility the relativization of the considered scheme to be carried out. Finally, it is asserted, that the correspondent hadron classification is relativistic invariant.     

Investigation of possible half-metal material on double perovskites Sr2BBO6 (B,B=3d transition metal) using first-principle calculations

We investigated the possible candidates of half-metal (HM) material in double perovskites structure Sr₂BB′O₆ (B, B′=3d transition metal). The electronic structure calculations were based on density functional theory (DFT) with both generalized gradient approximation (GGA) and GGA+U approaches, where +U is on-site Coulomb interaction correction. With the consideration of 4 types of magnetic states, i.e. ferromagnetic (FM), ferromagnetic (FiM), antimagnetic (AF) and nonmagnetic (NM), we found 5 promising candidates for half-metallic (HM) materials: Sr₂ScCrO₆, Sr₂TiCrO₆, Sr₂MnCrO₆, Sr₂ZnMnO₆ and Sr₂ZnFeO₆.     

Wetting and interfacial adsorption in the Blume-Capel model on the square lattice

The structural and electronic properties of Cu_5-1 and Cu_6-1 nanowires with core-shell structures encapsulated inside a series zigzag (n,0) BeONTs denoted by Cu_5-1@(n,0) and Cu_6-1@(n,0) are investigated using the first-principles calculations within the generalized-gradient approximation. For Cu_5-1@(n,0) (10 ? n ? 17) and Cu_6-1@(n,0) (11 ? n ? 18) combined systems, the initial shapes (cylindrical BeONTs and CuNWs) are preserved without any visible change after optimization. The quantum conductances 5G ₀ and 6G ₀ of the most stable Cu_5-1@(12,0) and Cu_6-1@(13,0) combined systems are identical to the corresponding free-standing Cu_5-1 and Cu_6-1 nanowires, respectively. The energy bands crossing the Fermi level in both the Cu_5-1@(12,0) and Cu_6-1@(13,0) combined systems are all originated from the inner CuNWs. Therefore the electron transport will occur only through the inner CuNWs and the outer inert BeONTs serves well as an insulating cable sheath. The robust quantum conductance of the Cu_5-1 and Cu_6-1 nanowires, the insulating protection character of the (12,0) and (13,0) BeONTs and the highest stability of the tube-wire combined systems make the Cu_5-1@(12,0) and Cu_6-1@(13,0) combined systems are top-priority in the ULSI circuits and MEMS devices that demand steady transport of electrons.     

Gauged N = 8 supergravity in five dimensions

We construct gauged N = 8 supergravity theories in five dimensions. Instead of the twenty-seven vector fields of the ungauged theory, the gauged theories contain fifteen vector fields and twelve second-rank antisymmetric tensor fields satisfying self-dual field equations. The fifteen vector fields can be used to gauge any of the fifteen-dimensional semisimple subgroups of SL(6,R), specially SO(p, 6?p) for p = 0, 1, 2, 3. The gauged theories also have a physical global SU(1,1) symmetry which survives from the E₆₍₆₎ symmetry of the ungauged theory. This SU(1,1) for the SO(6) gauging is presumably related to that of the chiral N = 2 theory in ten dimensions. In our formalism we maintain a composite local USp(8) symmetry analogous to SU(8) in four dimensions.     

Phases of resonant amplitudes: πN → ϱN

Using SU(6)_W symmetry in its l-broken form we find that the newly reported relative signs of πN → ?N resonant amplitudes seem to indicate a universal “SU (6)_W-like” preference for all observed multiplets. Since the corresponding πN → πΔ phases favour an “anti-SU(6)_W” solution for the 70, L^P = 1^? multiplet the l-broken SU (6)_W model now faces a serious contradiction.     

Microwave spectrum of monodeuterated diacetylene due to vibrationally induced dipole moment

Microwave spectrum of monodeuterated diacetylene (HCCCCD), which is nonpolar in the equilibrium configuration, was observed in various excited states of bending vibrations. Dipole moments in the ν₆, 2ν₆, and ν₆ + ν₉ vibrational states were determined from the Stark effect measurement to be 0.0907(6), 0.1681(14), and 0.0900(4) D with uncertainties in parentheses, where ν₆ and ν₉ denote respectively the CCH bending and lowest frequency bending vibrations. The l-type doubling constant in the ν₆ state is 2.1316(28) MHz. Rotational constants were determined in MHz; ν₆(Π), 4086.2165(44); 2ν₆(Δ), 4087.6963(58); ν₆ + ν₉(Δ), 4097.7537(50); 2ν₈(Δ), 4094.4786(103); ν₆ + ν₇(Δ), 4092.9074(176); ν₇ + ν₈(Δ), 4095.8925(354); 2ν₆ + ν₉(Φ), 4098.9505(339).     

Determination of isotope shift crossed-second-order-effects and hyperfine-structure parameters in the Eu I configuration 4f 7 6s7s

In the Eu I configuration 4f ⁷(⁸ S)6s7s the isotope shift (IS) and hyperfine-structure (hfs) of the levelse ⁸ S _7/2 andf ⁸ S _7/2 were determined from the transitions 684.5 nm, 733.7 nm and 821.0 nm to 4f ⁷6s6p. Together with experimental results of our previous measurements a theoretical analysis of the IS and hfs for the complete configuration 4f ⁷ 6s7s can now be carried out. From the IS of the four 6s7s-levels we evaluated the two crossed-second-order-parametersg ₃(4f,6s)= ?l.l(l)mK andg ₃(4f, 7s)= ?0.1(l)mK. The ratiog ₃/G ₃ is determined for various Eu configurations and found to be equal to 5.6(3)·10^?6 in complete agreement with a theoretical value following from Hartree-Fock calculations. The single electron hfs splitting constantsa ¹⁰(4f)= ?1.9 (3) mK,a ¹⁰(6s)=396(3)mK, anda ¹⁰(7s)=65(3)mK are also determined and compared with those of other Eu configurations.     

Structure and magnetic properties of TbFe6−xGa6+x compounds

The TbFe_6−xGa_6+x compounds (x=0, 0.5, 1.0 and 1.45) have been prepared and studied by X-ray powder diffraction and magnetization measurements. The structure of the compound TbFe_6−xGa_6+x transfers from the orthorhombic ScFe₆Ga₆-type structure (space group Immm) (x=0 and 0.5) to the tetragonal ThMn₁₂-type structure (space group I4/mmm) (x=1.0 and 1.5) and the volume of the unit cell increases as Ga content increases. The lattice parameters are a=0.85551, b=0.8626 and c=0.50717 nm for TbFe₆Ga₆, and a=0.86938 and c=0.50918 nm for TbFe_4.55Ga_7.45.The magnetization measurements indicate all the TbFe_6−xGa_6+x compounds have magnetic ordering. The Curie temperatures decrease from 492 K for TbFe₆Ga₆ to 327 K for TbFe_4.55Ga_7.45. The magnetization of the TbFe_6−xGa_6+x decreases with temperature decreases below its magnetic ordering temperature due to the increasing Tb-sublattice magnetization which is antiparallel to the Fe-sublattice magnetization.     

Untersuchungen zum Stark-Effekt metastabiler Terme im Ba I-Spektrum durch Nachweis von Hochfrequenzübergängen

By detection of r.f.-transitions between Zeeman-sublevels the Zeeman-splitting of the metastable 6s 5d-levels and of the 6s 6p³ P ₁-level of the even Ba-isotopes was investigated under the influence of an electric field in addition to a magnetic field. From the measurements the following tensor polarizabilities were deduced: α_ten(³D₃)=?29(5) kHz/(kV/cm)², α_ten(³ D ₂)=?13(3) kHz/(kV/cm)², α_ten(³D₁)=?10(2) kHz/(kV/cm)², α_ten(¹ D ₂)=?16(3) kHz/(kV/cm)². No effect due to electric fields up to 50 kV/cm was observed in the Zeeman-splitting of the 6s 6p ³ P ₁-level. Therefore the tensor polarizability of the 6s 6p³P₁-level must be much smaller than those of the 6s 5d-levels. The results will be discussed by considering the oscillator strengths both of the infrared transitions between the two multiplets 6s 5d ³ D and 6s 6p ³ P and of transitions to other low lying levels.     

Quantum-chemical calculations of the piezoelectric characteristics of boron nitride and carbon nanotubes

The piezoelectric characteristics of boron-nitride and carbon nanotubes were calculated. The electronic structure of nanotubes was studied using the quantum-chemical semiempirical MNDO method within a molecular-cluster model. The piezoelectric constants e _zzz, e _xzz, and e _xxx of boron nitride nanotubes of two structural modifications (n, n) (n = 5, 6, ..., 9) and (n, 0) (n = 6, 7, ..., 12) were calculated. The values of the piezoelectric constants e _zzz of tubular boron nitride are found to be close in order of magnitude to the respective values obtained using nonempirical calculation methods. The piezoelectric constant e _xzz of a (6, 6) carbon nanotube doped with substitutional point defects was calculated.     

Experimental investigation of highly excited states of the 5,6He and 5,6Li nuclei in the (6Li, 7Be) and (6Li, 7Li) one-nucleon pickup reactions

The (⁶Li, ⁷Be) and (⁶Li, ⁷Li) reactions on ⁶Li and ⁷Li nuclei were investigated in the angular interval 0°–20° in the laboratory system at a ⁶Li energy of 93 MeV. In addition to low-lying states of the ^5,6He and ^5,6Li nuclei, broad structures were observed near the t(³He)+d and t(³He)+t thresholds at the excitation energies of 16.75 (3/2⁺) and ～20 MeV (for ⁵He), 16.66 (3/2⁺) and ～20 MeV (⁵Li), 14.0 and 25 MeV (⁶He), and ～20 MeV (⁶Li). The angular distributions measured in the ⁷Li(⁶Li, ⁷Be)⁶He reaction for transitions to the ground state (0⁺) and excited states at E _x=1.8 MeV (2⁺) and 14.0 MeV of the ⁶He nucleus were analyzed by the finite-range distorted-wave method assuming the 1p-and 1s-proton pickup mechanism. The (⁶Li, ⁷Be) and (⁶Li, ⁷Li) reactions were shown to proceed predominantly through the one-step pickup mechanism, and the broad structures observed at high excitation energies are considered as quasimolecular states of the t(³He)+d and t(³He)+t types.     

Isotope shift and hyperfine structure of the transition5d6s 2 2 D 3/2-5d6s6p 4 F 3/2 of Lu175 and Lu176

Using a tunable single mode dye laser the isotope shift of the 573.7 nm-line between the isotopes Lu¹⁷⁵ and Lu¹⁷⁶ has been determined to be IS(176?175, 573.7 nm)=?394(5) MHz yielding a change of mean square nuclear radii ofδ〈r ²〉=0.022(5) fm². In addition from our measurements the following values of the hyperfine splitting constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _3/2:A=?651.4(0.3) MHz,B=2,494(4) MHz 5d6s ^{2 2} D _3/2:A=138.0(0.3) MHz,B=2,131(3) MHz Lu¹⁷⁵ 5d6s6p ⁴ F _3/2:A=?924.7(0.5) MHz,B=1,767(4) MHz.     

Antigravitating black hole solitons with scalar hair in N=4 supergravity

We present some new solutions of the equations of the N=4 supergravity theory which represent black holes with scalar, electric and magnetic charges. The solutions are parameterized by the mass and 6 electric and 6 magnetic charges which can be assembled into a complex 6-vector, Z^N. One can act on the solutions with SO(6)×U(1) to obtain new solutions with the same mass M but charges Z^N related by SO(6)×U(1) transformations, the U(1) factor corresponding to the duality subgroup of the hidden SU(1, 1) ssymetry of the N=4 model. In a certain limiting case the black holes have zero temperature and behave like solitons. In this case multisoliton solutions are exhibited which antigravitate, i.e. are in static equilibrium. We also present some solutions of the Kaluza-Klein theory which were anticipated by Scherk which also antigravitate. However, these latter solutions contain naked singularities. A discussion is also given of the relation of these solutions to dimensional reduction which has relevance for the black holes in the N=8 supergravity theory.     

D3+D6 solution and D4+D6 solution

We make the supergravity solutions describing the branes (D3 branes and D4 branes) localized within the D6 branes in the near core region of D6 brane. From the D=11 solutions (M3 branes and M4 branes with the Z_N identifications in the transverse space) we obtain the D=10 supergravity solutions of D3 branes localized within D6 branes and D4 branes localized within D6 branes by reducing the dimension down to D=10 along a circular direction of S³ part of the transverse space. M3 brane solution leads to D=10 background representing D3 branes localized on D6 branes in the region close to the D6 branes core. M4 branes lead to the D4 branes localized on D6 branes in the region close to the D6 brane core.     

Level crossing investigation of the hyperfine splitting in thez 6 P 7/2-level of EuI

By means of a level crossing experiment the hyperfine structure constants of thez ⁶ P _7/2-level of Eu have been determined. The results areA=-6.51(6) MHz andB= 131.2(1.0) MHz in the isotope¹⁵¹Eu andA=-2.84(3) MHz andB=327.5(1.5) MHz in the isotope¹⁵³Eu. Experimental data on the hyperfine splitting are available now for 11 of the 12 levels of the configuration 4f ⁷ (⁸S)6s 6p of EuI. These data are compared with the theoretical interpretation given by Bordarieret al. [1] which was based on only 7A-factors andB-factors. It is shown that the agreement between theory and experiment can be improved by taking into account configuration interactions.     

Sonochemical effect on two new Ruthenium(II) complexes with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline precursors for synthesis of RuO2 nanoparticles

Two novel Ru(II) complexes [(η⁶-p-cymene)RuCl(L2)]PF₆ (R2) and [(η⁶-C₆H₆)RuCl(L2)]PF₆ (R4), with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline (L2), were synthesized and characterized by elemental analysis, ¹H NMR, ¹³C NMR and IR spectroscopy. Based on X-ray crystallography studies, complexes R2 and R4 have coordination environments with formulated (η⁶-p-cymene)Ru(N₂Cl) and (η⁶-C₆H₆)Ru(N₂Cl), respectively. The thermal stabilities of compounds R2 and R4 were studied by thermal gravimetric (TG) and differential scanning calorimetry (DSC). Thermal decomposition of these complexes was at 280 °C and 260 °C under air atmosphere respectively. The interaction of these complexes with calf thymus DNA (CT-DNA) was explored through electronic absorption spectra, fluorescence and redox behavior studies. The results showed that the complexes bind to CT-DNA with electrostatic interactions. Nanoparticles of RuO₂ were prepared by calcination of R2 and R4. Also the role of the ultrasound waves on the characteristics of the RuO₂ nanoparticles was studied. The nanoparticles were characterized by IR spectroscopy and X-ray diffraction (XRD). Also size and morphology of nanoparticles were studied by scanning electron microscopy (SEM).     

Photoluminescence of 1,3-Diphenyl-1H-pyrazolo[3,4-b]quinoline and its derivatives: Experiment and quantum chemical simulations

The optical absorption and photoluminescent spectra are studied in recently synthesized diphenyl pyrazoloquinolines (DPPQ): 1,3-diphenyl-1H-pyrazolo[3,4-b] quinoline and its 6-vinyl, 6-N,N-diphenyl, 6-methyl, 6-fluoro, 6-bromo and 6-chloro derivatives. The photoemission spectra are recorded in organic solvents of different polarity and found to be highly solvatochromic. The measured spectra are compared with the quantum chemical calculations performed by means of the semiempirical methods (AM1 or PM3) in combination with the equilibrium molecular conformation (EMC) in vacuo (T = 0 K, Γ = 0.12 eV) or MD simulations (T = 300 K). The broadening of absorption and emission bands and their red-shift with increasing of temperature may be well reproduced by MD simulations. The Stokes shift of the photoluminescent spectra is obtained by including vibrational modes into the emission equation. The quantum chemical method AM1 in combination with MD simulations gives in most cases the best agreement with the experimental data. By comparing the emission spectra of 6-N,N-diphenyl-DPPQ with other DPPQ-derivatives one concludes that the molecular fragment diphenyl-amin [(C₆H₅)₂N-] is likely subjected to strong conformational changes in solvents. The large difference between the excited- and state-dipole moments indicates on a strong electron transfer effect being common for all DPPQ derivatives.