Yang-Mills and Dirac Fields with Inhomogeneous Boundary Conditions

Finite time existence and uniqueness of solutions of the evolution equations of minimally coupled Yang-Mills and Dirac systems are proved for inhomogeneous boundary conditions. A characterization of the space of solutions of minimally coupled Yang-Mills and Dirac equations is obtained in terms of the boundary data and the Cauchy data satisfying the constraint equation. The proof is based on a special gauge fixing and a singular perturbation result for the existence of continuous semigroups. Received: 18 April 1996 / Accepted: 3 March 1997     

Reactions of hydroxymethyl derivatives of uric acid with oxiranes: Recognition of mechanism based on kinetic studies

Kinetic and mechanistic studies on the reaction between 1 equivalent of 1,3,7,9‐tetrakis(hydroxymethyl) ureate with 1 equivalent of oxirane (ethylene oxide or propylene oxide) are presented. This study led to recognition of the mechanism of reaction. It has been found that during the reaction the release of formaldehyde from hydroxymethyl groups blocked with oxirane occurs. The formaldehyde is consequently bound to the end of etherol chain. Owing to this rearrangement, the amount of formaldehyde remains constant during the process. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 345–350, 2006     

Reactions of the N,N-dialkylpyridylcarboxylic amides with lithium amides. Regioselective lithiation of N,N-diisopropylpyridylcarboxylic amides,a useful method for synthesis of 2,3- and 3,4-disubstituted pyridines

The behaviour of the N,N-dimethyl-, N,N-diethyl- and N,N-diisopropylpyridylcarboxylic amides in the reactions with Et₂NLi and iPr₂NLi, and a convenient way of synthesis of 2,3- and 3,4-disubstituted pyridines, by the direct lithiation of N,N-diisopropylamides leading subsequently to the ortho new CC bonds formation, are described.     

Electronic States and Schottky Barrier Height at Metal/MgO(100) Interfaces

Using an ab initio total energy approach, we study the electronic structure of metal/MgO(100) interfaces. By considering simple and transition metals, different adsorption sites and different interface separations, we analyze the influence of the character of metal and of the detailed interfacial atomic structure. We calculate the interface density of states, electron transfer, electric dipole, and the Schottky barrier height. We characterize three types of electronic states: states due to chemical bonding which appear at well defined energies, conventional metal-induced gap states associated to a smooth density of states in the MgO gap region, and metal band distortions due to polarization by the electrostatic field of the ionic substrate. We point out that, with respect to the extended Schottky limit, the interface formation yields an electric dipole mainly determined by the substrate characteristics. Indeed, the metal-dependent contributions (interfacial states and electron transfer) remain small with respect to the metal polarization induced by the substrate electrostatic field.     

Hydrogen bonding in linear (LiH)2

Ab initio LCAO MO SCF calculations are reported on the linear form of LiH dimer. The properties and structure of the Li-H-Li linkage are discussed in the light of hydrogen bonding.     

A unification of boson expansion theories: (I). Functional representations of fermion states

The method for obtaining boson expansion by representing the fermion states as holomorphic functions of many complex variables is presented. Such functional representation is explicitly constructed for each space which is the carrier space of an irreducible representation of a semisimple compact Lie group. This is achieved by proving the unity resolution in terms of holomorphically parametrized Perelomov's generalized coherent states. The functional images of fermion states are polynomials of complex variables, while those of fermion operators are differential operators of finite order with polynomial coefficients.     

Molecular mechanics of photopolymerization of 2,5-distyrylpyrazine in solid state

The molecular mechanics of photopolymerization of 2,5-distyrylpyrazine in the solid-state α form is investigated by a combination of Raman and electronic spectroscopic techniques. A stepwise photoreaction is used to stabilize an intermediate oligomer structure. For this purpose, the 476.5-nm argon-ion laser line is used to convert the monomer to the oligomer. The Raman phonon spectra reveal a homogeneous mechanism, with considerable lattice rearrangement, for the oligomerization process, which is also found to produce lattice strain. Further photoreaction of the oligomer is carried out with light of wavelength ≤400 nm from a 200-W mercuryxenon lamp as well as with the 355- and 417-nm laser lines from a Nd: Yag laser system. The Raman phonon spectra, monitored during the conversion of the oligomer to the polymer, show that initially the process starts homogeneously, with considerable lattice rearrangment. Then it turns heterogeneous, with a phase separation accompanied by a gradual ordering of the polymer product lattice. The electronic absorption spectra of the monomer are characterized and related to the stepwise photo process discussed above. Although the emission spectra show a monotonic change during the photoreaction, energy transfer from the oligomer to the monomer and from the polymer to the oligomer obscures and quantitative characterization by emission spectroscopy.     

j3Δg state of the hydrogen molecule

The potential energy curve for the j³Δ_g state of the hydrogen molecule has been calculated in the Born-Oppenheimer approximation. Highly flexible wavefunctions depending explicitly on the interelectronic distance have been used. The vibrational Schrödinger equation for the j state has been solved for H₂, HD, and D₂. The results are compared with the available experimental data, and it is shown that the adiabatic and nonadiabatic effects are mainly responsible for the existing discrepancy. The singlet-triplet separation for the j-J pair of states is also discussed.