Analysis of variations in the thermal neutron flux at an altitude of 1700 m above sea level

The results of detection of thermal neutron flux by a large open scintillation detector of thermal neutrons are reported. Detailed analysis of the experimental data is performed. Meteorological, astronomical, and geophysical aspects of the variations observed are considered.     

Core photoionization satellites in fullerence and related model systems

The so-called shake-up satellites accompanying C_1s photoionization in C₆₀ have been studied theoretically by means of INDO /CI . It is found that the lowest shake-up satellites in C₆₀ correspond to global charge-transfer excitions that move charge from the opposite side of the fullerence cage to the core-hole region, whereas higher-energy satellites tend to move charge from regions nearer to the core hole. Analogies are drawn, with, on the one hand, smaller model molecules such as napthalene and acenaphtylene and, on the other hand, infinite systems such as graphite. © 1994 John Wiley & Sons, Inc.     

Ab-initio calculations of pair-correlation effects on the hyperfine structure of the 4s 4p and 4s 3d configurations of Ca

The hyperfine structure of the 4s 4p and 4s 3d configurations of Ca has been evaluated using many-body perturbation theory. Single excitations and pair-correlation effects have been included by solving coupled one-particle and two-particle differential equations numerically. The correlation between the valence electrons has been treated selfconsistently by solving these equations iteratively for the valence pair. Core-polarisation effects have been evaluated by hyperfine-induced single-particle functions. From the calculated and experimental results of the two configurations,Q=?49(5) mb has been evaluated for the nuclear quadrupole moment of⁴³Ca.     

Photochemistry of p-chloromercurobenzophenone: Photoreduction as an alternative to demercuration

p-Chloromercurobenzophenone exhibits dual reactivity during photolysis: in solvents that are hydrogen donors it is photoreduced with the formation of a mercury-containing ketyl radical, while in other solvents it undergoes demercuration. Photolysis of p-chloromercurobenzophenone by both paths occurs from the triplet excited state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1738–1742, August, 1990.     

Charge delocalization and enhanced acidity in tricationic superelectrophiles

This Article presents the results from studies related to the chemistry of tricationic superelectrophiles. A series of triaryl methanols were ionized in Br?nsted superacids, and the corresponding tricationic intermediates were formed. The trications are found to participate in two types of reactions; both are characteristic of highly charged organic cations. One set of reactions occurs through charge migration. A second set of reactions occurs through deprotonation of an unusually acidic site on the tricationic species. One of the tricationic intermediates has been directly observed by low temperature NMR spectroscopy. These highly charged ions and their reactions have also been studied using density functional theory calculations. As a result of charge migration, electron density at a carbocation site is found to increase with progression from monocationic to pentacationic structures.