Determination of the isotope shift of115m Cd by a Zeeman scanning method

We have used an optical pumping-Zeeman scanning technique in order to determine the isotope shift in the 3,261 Å resonance line of 43-day, spin-11/2^115m Cd. A sample of ≈5×10¹² atoms was aligned in the¹ S ₀ diamagnetic ground state by optically pumping the sample with one selected Zeeman-scanned component of the³ P ₁?3,261 Å resonance line from a¹¹⁴Cd lamp. The alignment was detected through the modulation of the pumping beam at the nuclear resonance frequency. Thus by Zeeman scanning theF = 9/2 component of the³ P ₁ level and using previously determinedA- andB-values, we findδ5v(114–115m (9/2))= ?4,234(48) MHz and¹¹⁴Cd-^115mCd isotope shift = 87(48) MHz. We calculate a staggering parameterγ(^115mCd)=0.73(26), and a change in mean-square nuclear charge radiusδ〈r ²〉^114,115m =0.035(18)fm².     

Synthese de tetrahydrodibenzofurannes : creation d'un carbone quaternaire par transposition de claisen.

A new route to tetrahydrodibenzofurannes is described. It is based upon Claisen transposition of an aryloxycyclohexene to $\text{o}$.hydroxyphenyl cyclohexene which is, in turn, cyclized by palladium acetate. In the studied example, an overall yield of 45 % is obtained in two steps. The isolation of an unexpected minor isomeric transposed compound sets a problem of mechanism.     

Distribution of nuclear magnetization in mercury isotopes

Examination of the systematics of ten mercury isotopes, for which there exist precision measurements of both the nuclear magnetic dipole moments and hfs interaction constants A (6s 6p ³P1), shows a relation between the magnetic moments and the magnetic dipole hfs anomalies.     

Synthese du noyau dihydro-5,6 s-triazolo[2,3-d] henzoxazepine-1,4

2-Ethylthio-5 methylene-6H-s-triazolo[2,3-d][1,4] benzoxaze-pine, a new heterocyclic ring system, has been synthesized by cyclisation of the appropriate propargyloxyphenyltriazole. Nucleophilic addition of a triazole nitrogen atom also yields three isomeric by-products, mainly a s-triazolo[2,3-e] [1,5]benzoxazocine.     

Simultaneous imaging of total cerebral hemoglobin concentration,oxygenation, and blood flow during functional activation

A simple instrument is demonstrated for high-resolution simultaneous imaging of total hemoglobin concentration and oxygenation and blood flow in the brain by combining rapid multiwavelength imaging with laser speckle contrast imaging. The instrument was used to image changes in oxyhemoglobin and deoxyhemoglobin and blood flow during cortical spreading depression and single whisker stimulation in rats through a thinned skull. The ability to image blood flow and hemoglobin concentration changes simultaneously with high resolution will permit detailed quantitative analysis of the spatiotemporal hemodynamics of functional brain activation, including imaging of oxygen metabolism. This is of significance to the neuroscience community and will lead to a better understanding of the interrelationship of neural, metabolic, and hemodynamic processes in normal and diseased brains.     

Monte Carlo calculations of atoms and molecules

The variational and Green's function Monte Carlo (GFMC) methods can treat many interesting atomic and molecular problems. These methods can give chemical accuracy for up to 10 or so electrons. The various implementations of the GFMC method, including the domain Green's function method and the short-time approximation, are discussed. Results are presented for several representative atoms and molecules.     

Algorithms for nonlinear integer bicriterion problems

Two algorithms to solve the nonlinear bicriterion integer mathematical programming (BIMP) problem are presented. One is a noninteractive procedure that generates the entire efficient set, and the second one is an interactive procedure that determines the best compromise solution of the decision maker (DM). A Tchebycheff norm related approach is used for generating the efficient points for the BIMP problem. An application of the interactive procedure for a quality control problem is also presented.This research was supported by the National Science Foundation Grant No. ECS-82-12076 with the University of Oklahoma.