In-beam gamma-ray and electron spectroscopy following the75As(p,n)75Se reaction

The level scheme of⁷⁵Se has been studied through the⁷⁵As (p, n) reaction at proton energies from 1.5 to 5.0 MeV.γ-ray and internal conversion electron measurements were made using NaI (T1) and Ge(Li) detectors and a six-gap electron spectrometer. A proportional counter and a thin window NaI(T1) detector were used to detectγ-rays with energies less than 30 keV. The level scheme has been established by observing the thresholds of variousγ-rays and byγ-γ and e^?-γ coincidence measurements. New levels at 133.0, 293.2, 790.0, 953.0, 1020.8, 1184.3, 1198.5 and 1258.2 keV not observed in earlier (p, n) studies have been established. Conversion coefficients of most of the low-lying transitions have been determined. Angular distributions of some of theγ-rays were also measured and compared with the statistical model calculations. DefiniteJ ^π assignments have been made to most of the low-lying levels. Life-times of the 112.1, 133.0, 286.7 and 293.2 keV levels have been measured to be 0.69±0.12, 5.3±0.6, 1.35±0.15 and 31±2 nsec respectively. The reduced transition probabilities for various low-lying transitions have been determined and compared with recent calculations. The 1/2^? and 9/2⁺ levels hitherto unknown in this nucleus has been identified. The structure of the low-lying levels is discussed in terms of the existing models.     

A consistent form of reduced density matrices of superfluids

The present paper aims at deriving a systematic expression of the second order reduced density matrixΩ ₂ in the case of a condensed system of identical spinless bosons. The derivation lends itself to generalization leading to higher order reduced density matricesΩ _n ,n>2, that are consistent with the hierarchical set of equations of motion for the differentΩ _n .     

Determination of the amine content of chitosan by pyrolysis-gas chromatography

Pyrolysis-gas chromatography-mass spectrometry has been applied to the study of N-acetyl-d-glucosamine, chitin and chitosans of varying degrees of deacetylation prepared from chitin. An examination of the pyrograms of samples of chitosan revealed that there is a direct correlation between the amine content and the ratio of the areas of the peaks derived from the glucosamine and N-acety-d-glucosamine moieties.     

Nitrosoarene-CuI complexes are intermediates in copper-catalyzed allylic amination

Reactions of nitrosobenzene and N,N'-diethyl-4-nitrosoaniline with [Cu(CH3CN)4]PF6 produce novel homoleptic Cu(I)-nitrosoarene complexes, [Cu(ArNO)3]PF6, 1 (Ar = Ph) and 2 (Ar = 4-Et2NC6H4NO). The X-ray structure of 2 reveals that the copper is coordinated in a severely distorted trigonal planar geometry to the N-atom of the nitrosoarene ligand. Reactions of the PhNO complex 1 with olefins and an olefin/diene mixture provide evidence for its role as an intermediate and possibly the active nitrogen transfer agent in the Cu-catalyzed allylic amination of olefins by aryl hydroxylamines.     

A systematic scheme of qualitative analysis for anions. III

The completeness of precipitation of anions and basic radicals by the two group reagents, zinc acetate and cadmium nitrate, has been investigated. It has been shown that the two reagents precipitate many of the anions quantitatively and can thus be used for their gravimetric estimation.     

A study of the vestigial records of cosmic rays in lunar rocks using a thick section technique

An experimental technique has been developed for systematic measurements of fossil tracks along selected planes cut from grains and rocks. With controlled etching, the technique allows successive revelation of tracks in different minerals in the same section, a typical sequence being olivine, anorthite, clinopyroxene. It thus becomes possible to study precisely the cosmic ray track density variations over dimensions much greater than those of individual crystals. The technique also provides accurate information on the relative recording characteristics of different minerals present in a rock and cosmic ray tracks can be studied with a minimum interference of tracks due to spontaneous fission of uranium and transuranic elements. Continuous chains of sections, each section measuring approximately 1 cm., have been cut along several different planes in fifteen rocks from Mare Tranquillitatis, Oceanus Procellarum and Fra Mauro region. The cosmic ray track measurements from these sections have provided dramatic evidence for a number of processes affecting lunar rocks. The statistical, and non-uniform nature of erosion by micrometeorite bombardment can be seen in sections intersecting exposed surface which show regions of very steep track density gradients interspersed with eroded regions having lower track densities. The thick section technique permits determination of the energy spectrum of VH nuclei from track density gradients that extend over distances limited only by the dimensions of the rock, and, more important, in samples of identical orientation. The latter is particularly important in higher energy regions (deeper within the rock) where variations in crystal orientation cause track density differences of the same order as real changes in the gradient. Also in the near surface regions of rocks where low energy particles produce steep track density gradient, the thick section method has proved indispensable since it permits accurate depth determinations not possible in the spot sampling procedure. In this paper the technique of studying track profiles in thick sections is described. Although developed primarily for studying lunar samples, the thick section technique is also useful for similar studies in meteorites, particularly for gas-rich meteorites containing irradiated grains. In contrast to single grain studies, thick sections preserve the grain boundaries and permit accurate depth—density measurements. In addition thick section studies have revealed occasional large uniformly irradiated lithic fragments which would not have been possible to discover by spot sampling methods.