Simplified components of the spin-other-orbit interaction near the middle of the atomic f shell

To honour the memory of Brian Garner Wybourne, an analysis is presented of three components of the spin-other-orbit interaction for f electrons using the kind of Lie groups he would have been familiar with. The components have been named z ₆, z ₈ and z ₁₀. They all belong to the irreducible representation (IR) (30) of Racah’s group G₂. Near the middle of the f shell it is often found that fewer independent blocks of numbers are needed to express their matrix elements than the Wigner–Eckart theorem, generalized to the IRs U of G₂, would indicate. Each block corresponds to a given U and U?′, and possesses rows and columns labelled by the angular momenta L and L′. The number of independent blocks would be expected to be given by Racah’s multiplicity function c(UU?′ (30)); but near the middle of the shell the number c(UU?′ (20)) (or less) often suffices. For this to occur, z ₈ and z ₁₀ have to be replaced by linear combinations corresponding to IRs of the types (20)×(10) and (21)×(10) of the direct product group G_2A×G_2B, where A and B refer to electrons with their spins up (A) and spins down (B). A detailed example is provided by the IR (31) of G₂, which occurs in the configurations f ⁵ through f ⁹. In addition, two antiHermitian operators (z _a6 and z _a7) that also belong to the IR (30) of G₂ are discussed.     

Radionuclide and chemical hazards of a radium ore revigator

A study to characterize the radionuclide and chemical components in a radium-ore revigator has been completed. Measured activities of dissolved ²²²Rn, ²²⁶Ra, and U isotopes, determined in the water using radioanalytical techniques, exceeded recommended limits in drinking-water supplies. Trace-metal concentrations, determined using inductively coupled plasma mass spectrometry, increased in the water with exposure time and exceeded recommended drinking-water limits for V and As. The contribution to, and dose from, the airborne radon-gas level in a room due to radon emanation from a revigator were evaluated. The annual committed effective dose resulting from consuming the radionuclides in the revigator water were estimated to be ~100 μSv/y for combined uranium and radium.     

Selection rules forG 2 vectors in the atomicf shell

In various tabulations of such spectroscopic coefficients as the matrix elements of tensor operators or fractional parentage coefficients, it is found that many entries are unexpectedly zero. A survey is made of all cases that occur in the atomicf shell and that involve the 7-dimensional vector representation of the groupG ₂. Direct explanations are given in terms of the group structure of the electronic configurations that comprise the shell. The techniques used depend on a splitting of the state space into “spin-up” and “spin-down” parts, and, for other cases, the extensive use of the methods of second quantization. TheF terms of the atomicf shell are found to split into three classes. The separation that this classification provides for the twoF terms belonging to the irreducible representation (31) ofG ₂ coincides with Racah's separation. An improved separation of theH states of (31) is described.     

Access to substituted trifluoromethyl ketones using the versatile synthetic intermediate (E)-1,1-dimethyl-2-(1,1,1-trifluoropropan-2-ylidene)hydrazine

The N,N-dimethylhydrazone of 1,1,1-trifluoroacetone, (E)-1,1-dimethyl-2-(1,1,1-trifluoropropan-2-ylidene)hydrazine, has been shown to undergo a diverse set of reactions following deprotonation with n-butyl-lithium; including alkylation, addition to ketones and aldehydes, as well as palladium-catalyzed cross-couplings with aryl bromides. Mild hydrolysis of the N,N-dimethylhydrazone products from these transformations affords the corresponding trifluoromethyl ketones in good to excellent yields.     

Trace Metals Analysis of Legal and Counterfeit Cigarette Tobacco Samples Using Inductively Coupled Plasma Mass Spectrometry and Cold Vapor Atomic Absorption Spectrometry

ABSTRACT

A closed-vessel microwave-digestion method was developed for the determination of trace amounts of Be, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba, Tl, and Pb by inductively coupled plasma mass spectrometry and Hg by cold-vapor atomic absorption spectrometry in cigarette tobacco samples. In order to gauge the effectiveness of the digestion procedure, recovery studies were conducted using solutions prepared from National Institute of Standards and Technology Standard Reference Material 1573a Trace Elements in Tomato Leaves and Polish Certified Reference Material Virginia Tobacco Leaves. Limits of detection were below 1 µg g^?1 for all elements studied. Samples from two genuine-brand and three counterfeit packs were analyzed. The mean amounts of Be, As, Mo, Cd, Sb, Tl, Pb, and Hg were higher in counterfeit cigarettes, while the amounts of V, Cr, Mn, Co, Cu, Zn, Se, and Ba were comparable among legal and counterfeit cigarettes; the amount of Ni was higher in the legal cigarettes. Evaluation of Be, As, Mo, Cd, Sb, Tl, Pb, and Hg with their potential hazards for smokers is briefly discussed.     

A new route to sulfonamides via intermolecular radical addition to pentafluorophenyl vinylsulfonate and subsequent aminolysis

[reaction: see text] Various radical species generated from either the corresponding iodo- or bromo- compounds and tri-n-butyltin hydride were added in an intermolecular fashion to the activated acceptor pentafluorophenyl vinylsulfonate. The products of each reaction were then subjected to aminolysis with a variety of different amines.