Backward Terahertz Radiation from a Two-Color Femtosecond Laser Filament

A change in the quasistatic magnetic susceptibility in thin plates of iron borate (FeBO₃), which is a weak ferromagnet, has been revealed at adsorption of water molecules. The measurements have been performed at room temperature with the use of the magneto-optical Faraday effect. The change of the susceptibility in saturated water vapors is about 30%. The observed effect is reversible. The time of establishing the susceptibility after the introduction of water vapors is 1.5 min, which is twice as large as the time of establishing the susceptibility after the evacuation. The effect is explained by the appearance of uniaxial surface magnetic anisotropy in the basal plane because of the adsorption of water molecules.     

Anomalously interacting new extra vector bosons and their first LHC constraints

In this review phenomenological consequences of the Standard Model extension by means of new spin-1 chiral fields with the internal quantum numbers of the electroweak Higgs doublets are summarized. The prospects for resonance production and detection of the chiral vector Z* and W*^± bosons at the LHC energies are considered on the basis of quantitative simulations within the CompHEP/CalcHEP package. The Z* boson can be observed as a Breit-Wigner resonance peak in the invariant dilepton mass distributions in the same way as the well-known extra gauge Z?? bosons. However, the Z* bosons have unique signatures in transverse momentum, angular and pseudorapidity distributions of the final leptons, which allow one to distinguish them from other heavy neutral resonances. In 2010, with 40 pb^?1 of the LHC proton-proton data at the energy 7 TeV, the ATLAS detector was used to search for narrow resonances in the invariant mass spectrum of e ⁺ e ^? and ??⁺??^? final states and high-mass charged states decaying to a charged lepton and a neutrino. No statistically significant excess above the Standard Model expectation was observed. The exclusion mass limits of 1.15 and 1.35 TeV/c ² were obtained for the chiral neutral Z* and charged W* bosons, respectively. These are the first direct limits on the W* and Z* boson production. Based on the above, a novel strategy for the chiral boson search in the LHC dijet data is discussed. For almost all currently considered exotic models the relevant signal is expected in the central dijet rapidity region y _1,2 ? 0 and |y ₁ ? y ₂| ? 0. On the contrary, the chiral bosons do not contribute to this region but produce an excess of dijet events far away from it. In particular, for these bosons the appropriate kinematical restrictions lead to a dip in the centrality ratio distribution over the dijet invariant mass instead of a bump expected in the most exotic models.     

On the factors governing the minimum size of light beams during self-focusing

The final stage of self-focusing of 500-ps pulses of a neodymium laser in silicate and phosphate glasses and in the nonlinear liquids perfluorooctane, benzene, and toluene is studied theoretically and experimentally. The formation of spatial solitons, which are stable due to the nonlinearity saturation, is demonstrated. It is found that the intensity of the nonlinearity saturation is close to that of the threshold breakdown for glasses and the role of stimulated Raman scattering is significant for liquids.     

Mass spectra of acid and trisubstituted 1- and 2-adamantyl phosphites

The decomposition of acid and trisubstituted phosphites containing 1- and 2-adamantyl, cyclohexyl, and ethyl groups in various combinations was studied under electron impact. The major directions for the fragmentation of the compounds studied are related to cleavage of the C-O bond, which is accompanied by migration of one or two hydrogen atoms to the phosphorus-containing fragment. Mono-, di-, and triadamantyl phosphites feature the loss of phosphorous acid (in the case of acid phosphites) or alkylphosphorous acid (n the case of trisubstituted phosphites) from the molecular ion, which leads to the generation of a diadamantyl or alkyladamantyl species. In this case, the charge is localized predominantly on the hydrocarbon fragment.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1676–1678, July, 1990.     

Unexpected reaction of 1,1,1,10,10,10-hexafluorodecane-2,4,7,9-tetrone with methyl trifluoroacetate

Hexane-2,5-dione or 1,1,1,10,10,10-hexafluorodecane-2,4,7,9-tetrone react with methyl trifluoroacetate in the presence of LiH to give, upon treatment with diluted acid, 6-hydroxy-9-oxo-2,4,10-tris(trifluoromethyl)-3,11,12-trioxatetracyclo[5,2,1,0^2,6,0^4,10]dodecane. The structure of this compound was determined by X-ray diffraction study.     

Possibility of applying the electrochemical version of the Horner reaction to the synthesis of unsaturated lactones

Direct electrochemical reduction of specially synthesized 2-[(diethoxyphosphorylacetoxy] benzaldehyde on a platinum electrode in an aprotic medium is accompanied by ester bond cleavage, and not formation of coumarin via the phosphonate-anion followed by intramolecular Horner cyclization. This could be realized, as a matter of principle, in the presence of an ionol anion (2,6-di-tert-butyl-4-methylphenoxide), electrochemically generatedin situ.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 144–146, January, 1993.     

Electronic structure of benzenechromium tricarbonyl derivatives: The loss of conjugation between the π-aromatic system and the substituent of the coordinated ligand

Conclusions A study of the photoelectron spectra of benzenechromium tricarbonyl derivatives indicates the virtually complete loss of conjugation between the -aromatic system and the substituent of the coordinated ligand.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1425–1427, June, 1985.The authors express their gratitude to N. K. Baranetskaya and V. I. Losilkina for providing samples of the benzenechromium tricarbonyl derivatives studied.     

Determination of selenium and cadmium dopants in nanocomposites based on zinc and indium oxides by high resolution continuous source electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

An approach is proposed to the determination of selenium and cadmium dopants in new nanocomposites based on zinc and indium oxides. The approach is based on a combination of highly efficient high resolution continuous source electrothermal atomic absorption spectrometry (ETAAS) for the analysis of suspensions and inductively coupled plasma mass spectrometry for the analysis of solutions. A procedure is developed for the determination of Se and Cd dopants and matrix components based on Zn and In in nanocomposite solutions by inductively coupled plasma mass spectrometry. Stabilizing agents for the preparation of suspensions are studied for the ETAAS analysis of powders without their decomposition. The results of determination of CdSe dopants by high resolution ETAAS are validated by inductively coupled plasma mass spectrometry.     

Molecular structure of 3-aceto-5-cyano-6-dimethylaminohexa 3.5-dien-2-one and z-7-dimethylamino-2-aceto-4-methylhepta-2,4,6-trienecarboxylic acid methyl ester

X-ray structural analyses have been carried out for 3-aceto-5-cyano-6-dimethyl-aminohexa-3, 5-dien-2-one (I) and Z-7-dimethylamino-2-aceto-4-methylhepta-2,4,6-trienecarboxylic acid methyl ester (II). Introduction of an electron-withdrawing CN-group in the middle of the polyene chain in molecule (I) has been shown to reduce the degree of double bond delocalization. CNDO/2 calculations have also been performed for compound (I) and the resulting atomic charge distribution data are discussed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 396–402, February, 1991.The authors acknowledge the generosity of Zh. A. Krasnaya and T. S. Stytsenko for providing samples and for valuable discussons of the results.