(e, 3e) test on e-e correlations in helium

The angular variations of the five-fold differential cross section obtained by using different wave functions of helium are compared with experimental data. It is found that in the coplanar geometry two kinematical arrangements, (i) equal energy sharing between the two ejected electrons with one of them ejected along the momentum transfer direction and the other along varying direction and (ii) the Bethe ridge condition with fixed sum of ejected electron energies and varying angle between them, are very sensitive to e-e correlations contained in the target wave function. This comparison has been used to show that open-shell class of wave functions better incorporate e-e correlations than the closed-shell class.     

New sources of “active” halogen bis(dialkylamide)hydrogen dibromobromates, efficient reagents for destruction of ecotoxicants

Bis(dialkylamide)hydrogen dibromobromates were synthesized and their reactivity was investigated in decomposition of diethylphosphonic, diethylphosphoric, and 4-toluenesulfonic acids 4-nitrophenyl esters. The nucleophilic reactivity of a typical α-nucleophile, hypobromite ion, is independent of the source of the active bromine. The cetyltrimethylammonium dibromobromate is a unique reagent for destruction of ecotoxicants. In weakly alkaline media the half-life of 4-nitrophenyl diethylphosphonate did not exceed 6 s at [BrO^?] 0.02 mol l^?1, and the apparent reaction rate compared to water increased ～40-fold. The main factor governing the micellar effects of surfactants is concentrating the substrate in the micellar pseudophase.     

A study of the microstructure of thin a-C:H layers that orient liquid crystals

The surface structure of thin layers of a-C: H is studied by the method of island decoration, using silver films. The changes in the dimensions and density of silver particles is tracked by an electron microscope as a function of the thickness of the a-C: H layers. The electrical microprofile is discussed, along with the nature of the silver crystallization centers on the surface of the a-C: H layers. Zh. Tekh. Fiz. 68, 108–110 (January 1998)     

Theory of sheath in a collisional multi-component plasma

The aim of this brief report is to study the behaviour of sheath structure in a multi-component plasma with dust-neutral collisions. The plasma consists of electrons, ions, micron size negatively charged dust particles and neutrals. The sheath-edge potential and sheath width are calculated for collisionally dominated sheath. Comparison of collisionless and collisionally dominated sheath are made.     

Kinetics and mechanism of the reaction of benzoyl chloride with 4-(4′-N,N-dimethylaminostyryl)pyridine-N-oxide in toluene

The reaction of benzoyl chloride with 4-(4-N,N-dimethylaminostyryl)pyridine-N-oxide in toluene proceeds according to an addition—elimination mechanism. The rate and equilibrium constants of the individual steps were determined. An inhibiting effect of the substrate was detected.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 31, No. 5, pp. 316–318, September–October, 1995.     

Nucleophilicity of functional surface active substances in the transfer of phosphoryl groups

The reactivity of α-nucleophilic groups in functional detergents is comparable with those for analogous compounds which do not form micelles. Methods are proposed for the modification of surface active compounds to produce supernucleophilic systems for the decomposition of organophosphorus compounds. A new functional detergent — 1-cetyl-3-(2-hydroxyiminoethyl)imidazolium chloride-is the most powerful of the investigated surface active reagents capable of achieving half lives for the decomposition of 4-nitrophenyl diethyl phosphonate and 4-nitrophenyl diethyl phosphate of ≤2 and 14 s respectively. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 5, pp. 288–294, September–October, 2006.     

Role of the hydrophobic properties of functional detergents on micellar effects in the dissociation of environmental toxicants

1-Alkyl-3-(2-oximinopropyl)imidazolium chlorides were prepared with different alkyl chain lengths (Alk = C₁₂H₂₅, C₁₄H₂₉). Some physicochemical indices (CMC and pK _a^app) were determined. The reactivity of these compounds was studied in the dissociation of 4-nitrophenyl esters of diethylphosphonic, diethylphosphoric, and toluenesulfonic acids. The times for 50% conversion of the substrates into reaction products decrease in the series: C₁₂H₂₅ > C₁₄H₂₉ >C₁₆H₃₃. In selecting the direction of modification of the supernucleophilic functional surfactants, we should take into account not only their hydrophobic properties but also the efficiency of substrate solubilization as well as the reactivity of the oximate group in the surfactant micelles.     

Fast iterative methods for symmetric sinc-Galerkin systems

The symmetric sinc-Galerkin method developed by Lund, when appliedto the second-order self-adjoint boundary value problem, givesrise to a symmetric coefficient matrix has a special structureso that it can be advantageously used in solving the discretesystem. In this paper, we employ the preconditioned conjugategradient method with banded matrices as preconditioners. Weprove that the condition number of the preconditioned matrixis uniformly bounded by a constant independent of the size ofthe matrix. In particular, we show that the solution of an n-by-ndiscrete symmetric sinc-Galerkin system can be obtained in O(nlog n) operations. We also extend our method to the self-adjointelliptic partial differential equation. Numerical results aregiven to illustrate the effectiveness of our fast iterativesolvers.     

(e, 3e) Differential cross section of He (21 S) and He (23 S)

The angular distribution of the five-fold differential cross section for the electron impact double ionization of He (2¹ S) and He (2³ S) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to contribute very little in the triplet case.