The spectrofluorqmetric determination of anthracene, fluorene and phenanthrene in mixtures

A procedure is presented for the spectrofluorometric determination of mixtures of anthracene, fluorene and phenanthrene. The determination depends on differences in fluorescence emission spectra and on selective excitation of anthracene fluorescence. Some of the fluorescence and absorption spectra involved overlap, but these difficulties can be overcome by empirical corrections. The average relative error in this method is less than 5 % over the concentration range 0 to 5 ppm.     

Fission fragment angular distributions in 16O+181Ta

Time of flight and energy of fission fragments were measured using pulsed beam. Fission fragment mass and energy integrated angular distributions were extracted. Fission fragment anisotropy was explained in the framework of saddle point model.     

The fluorometric determination of o-phthalic acid

A fluorometric procedure for the determination of o-phthalic acid by conversion to fluoresceln is described. The optimum amount of o-phthalic acid for application of the method is 50–5000 μg. The determination can be carried out with a relative error of less than 5% even when significant quantities of common o-phthalic acid contaminants are present.     

Complementary variational principle and duality in mathematical programming

The relationship between the complementary variational principle and duality in mathematical programming is demonstrated through a geometric approach in a Hilbert space setting. A necessary and sufficient condition for the existence of such a principle is given in the case of a convex functional constrained by linear dynamics. Its relationship to the Kuhn-Tucker saddle point theory is indicated. Applications to various programming and control problems are discussed.     

PSI3: an open-source Ab Initio electronic structure package

PSI3 is a program system and development platform for ab initio molecular electronic structure computations. The package includes mature programming interfaces for parsing user input, accessing commonly used data such as basis‐set information or molecular orbital coefficients, and retrieving and storing binary data (with no software limitations on file sizes or file‐system‐sizes), especially multi‐index quantities such as electron repulsion integrals. This platform is useful for the rapid implementation of both standard quantum chemical methods, as well as the development of new models. Features that have already been implemented include Hartree‐Fock, multiconfigurational self‐consistent‐field, second‐order Møller‐Plesset perturbation theory, coupled cluster, and configuration interaction wave functions. Distinctive capabilities include the ability to employ Gaussian basis functions with arbitrary angular momentum levels; linear R12 second‐order perturbation theory; coupled cluster frequency‐dependent response properties, including dipole polarizabilities and optical rotation; and diagonal Born‐Oppenheimer corrections with correlated wave functions. This article describes the programming infrastructure and main features of the package. PSI3 is available free of charge through the open‐source, GNU General Public License. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007     

The total Position Spread in mixed‐valence compounds: A study on the model system

The behavior of the Total Position Spread (TPS) tensor, which is the second moment cumulant of the total position operator, is investigated in the case of a mixed‐valence model system. The system consists of two H₂ molecules placed at a distance D. If D is larger than about 4 bohr, the singly ionized system shows a mixed‐valence character. It is shown that the magnitude of the TPS has a strong peak in the region of the avoided crossing. We believe that the TPS can be a powerful tool to characterize the behavior of the electrons in realistic mixed‐valence compounds. © 2014 Wiley Periodicals, Inc.