Proton polarizability contribution to hydrogen hyperfine splitting

The contribution of proton polarizability to hydrogen hyperfine splitting is evaluated on the basis of modern experimental and theoretical results on the proton polarized structure functions. The value of this correction is equal to 1.4 ppm. Received: 10 July 2000 / Published online: 12 April 2002     

Toward solving the problem of the nuclear-motion effect on the fine structure of the hydrogen-like atom by the quasipotential method

Coulomb interaction in the hydrogen-like atom is investigated by using the scattering amplitude free from singularities. The quasipotential method makes it possible to obtain new contributions to the fine shift of energy levels to the sixth order in the fine-structure constant.     

A comparison of the reactivity of germylene and dimethylgermylene with some methylgermanes. Direct kinetic and quantum chemical studies

Time-resolved studies of germylene, GeH(2), and dimethygermylene, GeMe(2), generated by the 193 nm laser flash photolysis of appropriate precursor molecules have been carried out to try to obtain rate coefficients for their bimolecular reactions with dimethylgermane, Me(2)GeH(2), in the gas-phase. GeH(2) + Me(2)GeH(2) was studied over the pressure range 1-100 Torr with SF(6) as bath gas and at five temperatures in the range 296-553 K. Only slight pressure dependences were found (at 386, 447 and 553 K). RRKM modelling was carried out to fit these pressure dependences. The high pressure rate coefficients gave the Arrhenius parameters: log(A/cm(3) molecule(-1) s(-1)) = -10.99 +/- 0.07 and E(a) =-(7.35 +/- 0.48) kJ mol(-1). No reaction could be found between GeMe(2) + Me(2)GeH(2) at any temperature up to 549 K, and upper limits of ca. 10(-14) cm(3) molecule(-1) s(-1) were set for the rate coefficients. A rate coefficient of (1.33 +/- 0.04) x 10(-10) cm(3) molecule(-1) s(-1) was also obtained for GeH(2) + MeGeH(3) at 296 K. No reaction was found between GeMe(2) and MeGeH(3). Rate coefficient comparisons showed, inter alia, that in the substrate germane Me-for-H substitution increased the magnitudes of rate coefficients significantly, while in the germylene Me-for-H substitution decreased the magnitudes of rate coefficients by at least four orders of magnitude. Quantum chemical calculations (G2(MP2,SVP)//B3LYP level) supported these findings and showed that the lack of reactivity of GeMe(2) is caused by a positive energy barrier for rearrangement of the initially formed complexes. Full details of the structures of intermediate complexes and the discussion of their stabilities are given in the paper.     

New recoil-effect-induced contributions to the fine shift of S levels in the muonium atom

A new α ⁶ μ ³/(m ₁ m ₂) ln (m ₁ m ₂) correction that arises in one-photon particle interaction in the muonium atom is found and calculated.     

Cycloaddition of dialkylgermoles: synthesis and structures of 2,2,3,3-tetracyano-1,4,5,6-tetraphenyl-7-germanorborn-5-enes

Cycloaddition reactions of 1,1-dicyclopropyl-2,3,4,5-tetraphenyl-1-germacyclopentadiene (3) with dehydrobenzene, tetracyanoethylene, cyclooctyne, or dimethyl acetylenedicarboxylate as well as of 1,1-dimethy-2,3,4,5-tetraphenyl-1-germacyclopentadiene (4) and 2,3,4,5-tetraphenyl-1-germacyclopentadiene (5) with tetracyanoethylene or cyclooctyne were studied. Diels—Alder adducts of germoles3, 4, and5 with tetracyanoethylene were prepared. The structures of these adducts were established by X-ray diffraction analysis and their thermal and photochemical stabilities were examined. Published inIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1278–1284, July, 2000.     

Unstable halogen-containing organolithium compounds. 7. Thermodynamic calculations of the decomposition mechanism of halogen-containing organolithium compounds

Conclusions The influence of the halogen on the strength of the adjacent C-Li bond has been evaluated on the basis of thermodynamic and quantum-chemical calculations, and it has been shown that monomolecular decomposition is preferable for LiCHCl₂, LiCCl₃, LiCF₃, and o-FC₆H₄Li under the conditions of the experiment, while such decomposition is impossible for LiCH₂Cl.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2183–2186, October, 1979.     

Relativistic wavefunction and form factors of the bound system

An explicitly relativistically invariant three-dimensional formulation of the quasipotential method of Logunov and Tavkhelidze for the system of two particles with arbitrary spins and masses is given. This formalism is used to consider the matrix elements of local operators between bound states (the form factors of the bound system). The transformation law of the three-dimensional wavefunctions in the transition from the center of mass system to an arbitrary reference frame is obtained.     

Spectroscopy and Regge trajectories of heavy quarkonia in the relativistic quark model

The mass spectra of charmonia and bottomonia are calculated in the framework of the relativistic quark model up to high orbital and radial excitations. The Regge trajectories of heavy quarkonia are constructed both in the (J,M ²) and (n _r ,M ²) planes, where J is the total angular momentum and nr is the radial quantum number. All daughter trajectories turn out to be almost linear and parallel, while parent trajectories exhibit some nonlinearity. Such nonlinearity occurs only in the vicinity of ground states and few lowest excitations and is more pronounced for bottomonia, while it is only marginal for charmonia. The obtained results are compared with available experimental data, and a possible interpretation of the new charmonium-like states above open charm production threshold is discussed.