bluuebunny/crossref_metadata_2025_split huggingface dataset:
MÉthodes d'essais pour évaluer La toxicité des fumées de tir
Authors: Carbonel P. , Bigourd J. 
Published: December 2004

AbstractLe CERCHAR dispose de plusieurs méthodes pour évaluer la production de gaz toxiques dans les tirs d'explosifs: bombe de 115 1 où l'on tire 50 g ou 100 g d'explosif habituellement en présence de 150 kg de sable et sous atmosphère d'azote, chambre de 15 m3 où l'on tire 0,5 kg à 1 kg d'explosif en présence d'air, sous confinement variable (charge suspendue ou disposée dans un mortier d'acier avec ou sans bourrage et éventuellement avec un gainage). Les résultats d'essais montrent que la production de gaz toxiques varie beaucoup avec les conditions de tir: régime de détonation de l'explosif, travail accompli par les fumées de tir, réactions éventuelles des fumées avec l'oxygène atmosphérique ou avec les matériaux au contact de l'explosif (encartouchage, bourrage, gainage). Il semble que le tir en mortier d'acier avec bourrage dans la chambre de 15 m3 donne les résultats les plus proches d ce qu'on observe lors de tirs en mine. Cette méthode paraît donc préférable.
To the Problem of Standardization of the Safety Test for Permissible Explosives
Authors: Vetlický B. 
Published: December 2004

AbstractThe paper presents a proposal concerning a standard‐comparative test for permissible explosives used in various countries. Testing the explosives in a suspended charge or in various arrangements of the angle mortar with the reflective wall in an explosive methane/air mixture would create possibility of evaluating the behavior of permissible explosives under these model conditions and thus bringing valuable information not only for the present needs but also for the future development.
Modeling and Numerical Simulation of Combustion Process inside a solid‐propellant crack
Authors: Lu Yeu‐Cherng , Kuo Kenneth K. 
Published: December 2004

AbstractTransient combustion processes inside a solid‐propellant crack cavity have been formulated and solved numerically, with emphasis placed on the coupling between combustion dynamics and propellant grain deformation and fracture. Sample calculations were performed for a center‐perforated propellant grain with an existing crack. Parametric study investigating the effect of several physical properties on the initiation of fracture was also carried out. Numerical results indicated that the existence of cracks in a propellant grain may impose a safety issue for a rocket motor due to the creation of large free volume and extra burning surface area. Comparison of calculated results of this analysis and those which do not consider propellant deformation and fracture revealed that the coupling between combustion and structural analyses is mandatory for accurate simulation of crack combustion event. It was also found that, from the parametric study, fracture initiation is very sensitive to the magnitude of pressure exponent of the propellant burning rate.
Detonability limits of methane‐oxygen mixtures at elevated initial pressures
Authors: Bauer Pascal A. , Giraud Marc , Legendre Jean‐François , Catoire Laurent 
Published: December 2004

AbstractStudies and researches are conducted at ISL on the aero‐thermochemical launcher based on the RAM effect and entitled RAMAC. This type of launcher involves reactive gas mixtures which are chosen, in the thermally choked subsonic combustion mode, for their nondetonative properties. This paper gives the description of a new experimental facility at ISL, which involves a 90‐mm caliber detonation tube to carry out studies on reactive mixtures at initial pressures up to 5 MPa. First results for methane‐oxygen mixtures at 2.5 MPa and ambient temperature are given. Accordingly the upper detonability limits for these mixtures have been experimentally determined in 90 mm caliber. The experimental detonation velocities are compared with calculations by the Quartet thermochemical code.
Comparative Characteristic of Energy Content Calculating Methods for the furazan series as an example of energetic materials
Authors: Pivina Tatyana S. , Sukhachev Dmitrii V. , Evtushenko Aleksei V. , Khmelnitskii Lenor I. 
Published: December 2004

AbstractThe significant expenditures for organic synthesis of high‐energy materials necessitate an a priori evaluation of prospects for physical‐chemical parameters. The most important of these parameters is the heat of formation characterizing this or the other compound suggested for synthesis.This study describes and analyzes the most well‐known and widely used schemes and methods for evaluating and predicting the energy capacity of high‐energetic materials. The accuracy of calculations is evaluated for different schemes; the limits of their applicability are determined.
Physiological Activity of Dynamites Doped with Musk Xylene. (short communication)
Authors: Chruścielska K. , Skupiński W. 
Published: December 2004

AbstractComposition of catechol amines in a brain and a heart tissue of the adult male Wistar rate contacted with the DS‐1G3H dynamite doped with musk xylene has been studied. An increase of the norepinephrine concentration in the heart tissue was established.
Friction and impact sensitivity of formulations containing glycidyl azide polymer
Authors: Lusby C. A. , Ferguson D. C. , Husband D. M. 
Published: December 2004

AbstractThis paper describes work done to study the potential hazards of glycidyl azide polymer (GAP) based formulations. Friction and drop weight tests were performed on various GAP propellants, GAP mixed with different ingredients, and at different steps during processing of a propellant mix. The results showed that, under certain conditions, GAP formulations can be highly friction and impact sensitive.
Méthode des Biorbitales: Application Préliminaire au Calcul de l'Energie de l'Etat Fondamental de l'Atome de Beryllium
Authors: Bessis G. , Murez C. , Bratož S. 
Published: December 2004

AbstractL'énergie électronique de l'état fondamental de l'atome Be a été calculée en utilisant la méthode des biorbitales (SCF–BI) dans laquelle la fonction d'onde est représentée par un produit antisymétrisé de fonctions de paire identiques. Les fonctions de base sur lesquelles les biorbitales sont développées sont les orbitales s et p données par Watson. Les fonctions de paire introduites correspondent à des états singulets. L'énergie a été minimisée directement par un procédé de descente selon la pente maximale. On trouve 0,0414 u.a. pour l'énergie de corrélation soit 44% de l'énergie de corrélation théorique. On compare la méthode (SCF–BI) à la méthode (IC) d'interaction de configuration. On établit des relations entre les coefficients dans les deux méthodes. On donne les nombres d'occupation des orbitales.
A density functional representation of quantum chemistry. I. Motivation and general formalism
Authors: Primas H. 
Published: December 2004

AbstractThe molecular N‐electron problem is formulated in terms of the particle density 𝔔(r) = ∑σ(r − qn) and its canonically conjugated field. Weyl's representation of the canonical commutation relations is used and a characteristic functional of the molecular system is introduced as the expectation value of Weyl's functional exp {i(α, Q) + i(β, P)}. The Hamiltonian equation of motion for the characteristic functional is derived and its cumulant approximation is discussed. The first paper is restricted to a general discussion, independent of a special choice of the Hamiltonian.The density functional representation may be considered as a step towards a formulation of a renormalized quantum chemistry. The lowest order cumulants of the characteristic functional are accessible to actual precision measurements; on the other hand, most experiments are correctly represented by a characteristic functional of the Gaussian type. The significance of the higher order correlations is neither theoretically nor experimentally disclosed yet, their possible importance for biological systems is mentioned, and the question is raised of how far quantum mechanics is empirically confirmed for extremely complex systems.
The theory of local degeneracy
Authors: Joseph A. 
Published: December 2004

AbstractThe concept of a locally degenerate Hamiltonian is defined. It is shown that such a Hamiltonian is, with respect to a particular quantum number, degenerate in a single level only. Some examples of single‐particle systems suggested by a study of the stereographic projection are examined, a comparison being made with the Kepler problem. It is found, in these examples, that the degenerate level lies at the limiting value of the potential energy at large distances and the condition for the existence and the properties of these states are deduced. It is also shown that for such states certain operators may have eigenfunctions in common with the Hamiltonian and for this reason they are called local constants of the motion. Like ordinary constants of the motion, they help to simplify the eigenvalue problem and, in particular, the singular inverse square law potential is studied by this approach. Finally, the application of the results to resonance scattering (by bound states near the continuum) and to the calculation of the number of bound states is indicated.
Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCFMOLC(LCGO) Methode. VIII. Das System (Li2H)+
Authors: Diercksen G. , Preuss H. 
Published: December 2004

AbstractDas (Li2H)+ wurde unter Berücksichtigung aller 6 Elektronen mit dem Allgemeinen Programmsystem/SCFMOLC(LCGO) Verfahren im linearen Fall für 5 verschiedene Abstände RLiH berechnet, wobei das H‐Atom in der Mitte lag. Es ergab sich im Minimum eine Gesamtenergie von −15,289 a.E. der Bindungsabstand RLiH berechnet sich zu 3,14 a.E. Die Ionisierungsenergie beträgt dabei 15,1 eV. Die Bildungsenergie aus LiH und Li+ ergibt sich beim Vergleich der SCF‐Rechnungen an den beteiligten Systemen zu 59,7 kcal/mol (2,58 eV). Aus der Potentialkurve in der Nähe des Minimums berechnet sich die Kraftkonstante der symmetrischen Schwingung zu k = 0,13777 × 106 dyn/cm, aus der eine Frequenz ω = 577,9 cm−1 resultiert.
Application of the AMO method to non‐alternant systems
Authors: Silberman Z. , Gershgorn Z. , Pauncz R. 
Published: December 2004

AbstractThe alternant molecular orbital method (AMO) is more efficient if the molecular orbitals are chosen in an optimal way. A method is given of how to determine the most effective pairing scheme and how to choose the starting molecular orbitals. Applications to non‐alternant systems (fulvene and azulene) show that one can achieve substantial improvement in the energy by determining the best MO's.
A field theoretical description of states with different orbitals for different spins
Authors: Berggren K.‐F. , Johansson B. 
Published: December 2004

AbstractA field theoretical formulation is given for the method of different orbitals for different spins (DODS). For an infinite system DODS describes an antiferromagnetic state and to account for this spin ordering a Gorkov‐type of factorization is introduced. A corresponding gap equation is derived, where a non‐zero solution indicates the presence of long‐range order in the system. Actually the formulation given is general enough as to render DODS as a special case. As shown, we may also obtain a ferrimagnetic as well as a density wave state solution depending on the special characteristics of the system at hand.A related type of antiferromagnetism is described by the Overhauser spin density wave (SDW) state and also this theory is formulated in a field theoretical language. The similarities and differences between DODS and SDW are discussed. The energy expressions for the two states are given within the Hartree‐Fock approximation.It is proposed that the SDW state could be used to partly account for the correlation problem in molecules, as well as the method of DODS which has previously been employed for that purpose.
Open‐ and closed‐shell states in few‐particle quantum mechanics. I. Definitions
Authors: Kutzelnigg Werner , Smith Vedene H. 
Published: December 2004

AbstractThe distinction between open‐ and closed‐shell states is quite important in few‐particle quantum mechanics‐especially in view of the correlation problem. The current definitions of such states and of shells in general are, however, only meaningful if one can assume that the independent particle model is a valid description of the state under consideration. Definitions are given in terms of rigorous quantum‐mechanical concepts which allow a classification of states irrespective of any model assumptions. Closed‐shell states and different types of open‐shell states are distinguished. Sufficient criteria for a state to be a closed‐shell state are derived in terms of unitary invariants of the one‐particle density matrix of this state.
Open‐ and closed‐shell states in few‐particle quantum mechanics. II. Classification of atomic states
Authors: Smith Vedene H. , Kutzelnigg Werner 
Published: December 2004

AbstractThe system developed in the first paper of this series for the classification of states as open‐ or closed‐shed type is applied to atomic states. These may be classified in the isoelectronic limit (Z → ∞) from knowledge of the true wave function in this limit. One‐matrix occupation numbers are tabulated for a number of states of the first‐row atoms in the limit Z → ∞ and the states classified.A classification for finite Z is possible in the framework of the Z‐dependent perturbation theory by use of a thoerem for the stability of a closed‐shed with respect to small perturbations. Such a stability does not hold in general for open‐shel states.
Long‐range interactions between atoms and charges by double‐perturbation treatment
Authors: Landman U. 
Published: December 2004

AbstractA method of calculating the energy of the long‐range interaction between atoms and charges is presented. Simplification of the solution of the perturbation equations is achieved by a formal use of the “Double‐Perturbation Method”. Numerical results for the energies of the 2pσ state of HeH+2 are obtained.
Energy levels of paramagnetic ions: Algebra. II
Authors: Kibler Maurice 
Published: December 2004

AbstractThe correspondence rules between the algebra of coupling coefficients of the special unitary group SU(2) and the associated algebra of a subgroup G of SU(2) are presented. The matrix elements of the irreducible representations of G are written in a convenient quantization scheme and different relations between these matrix elements and the Clebsch‐Gordan coefficients of G are derived. Such a formalism is appropriate for numerous spectroscopic problems. As an example, it is applied to crystal field theory and electron paramagnetic resonance. General formulas from which a large number of results are rederived and generalized in a straightforward fashion are given. Numerical values of coupling coefficients for the tetragonal and cubic groups are listed in the Appendix.
Long range intermolecular forces between conjugated systems
Authors: Schweig A. 
Published: December 2004

AbstractThe long range intermolecular forces in terms of the interaction energies between two conjugated molecules are computed and discussed for the cases: (a) a point charge and ethylene, (b) two ethylene molecules, (c) two hexatriene molecules, (d) two benzene molecules, (e) two naphthalene molecules, and (f) two polar merocyanine molecules. The calculations are based on Buckingham's theory of long range intermolecular forces and the author's values for multipole moments and polarizabilities presented previously. The advantage of the treatment is: asymmetric molecules are correctly described and the intermolecular potential is better approximated than by the usual dipole approximation.
A model calculation of protonic mobility in ice
Authors: Kubarev S. I. , Shedrin M. I. 
Published: December 2004

AbstractThe protonic conductivity in ice crystals is considered within the framework of strong coupling developed earlier by the present authors for semiconductors with narrow bands and strong coupling of electrons with phonons. The generalization for a two‐band model is developed. The model used is the one described by Gosar and Pintar, the principal feature of which is the concept of the protonic conduction bands. The analytical expression for the protonic mobility is given. The results of the theory are in qualitative agreement with the experimental data.
The asymptotic Casimir–Polder potential from second‐order perturbation theory and its generalization for anisotropic polarizabilities
Authors: Craig D. P. , Power E. A. 
Published: December 2004

AbstractIt is shown how the leading term for very large R of the Casimir–Polder potential, that is the term varying as R−7, arises in second‐order perturbation theory applied to the interaction Hamiltonian − \documentclass{article}\pagestyle{empty}\begin{document}$ - \sum\limits_\sigma {\frac{1}{2}\alpha (\sigma){\rm E}^{ \bot ^2 } (\sigma)} $\end{document}. The generalization to anisotropic molecules is calculated and the angular dependence of the long range intermolecular potential in this case is given explicitly in terms of the principal polarizabilities and their corresponding directions of the two molecules.
Theory of two shells of atomic electrons using non‐orthogonal radial orbitals
Authors: Jucys A. P. , Bandzaitis A. A. , Grudzinskas J. J. 
Published: December 2004

AbstractA theory for handling non‐orthogonal radial orbitals of two shells of atomic electrons based on the mathematical apparatus of irreducible tensor operators is presented. The general expressions for one‐ and two‐electron operator matrix elements are given.
Natural orbital iterations for the ground state of nitric oxide
Authors: Kouba Joseph E. , Öhrn Yngve 
Published: December 2004

AbstractA method for the use of natural orbital iterations in limited CI calculations is discussed. This method is then applied to the ground X2II state of the nitric oxide molecule at its experimental equilibrium internuclear separation to yield the total energy, dipole moment, spin densities at each nucleus, and approximate natural spin orbitals for this molecule.
All‐electrons band structure of Polyene
Authors: André Jean‐Marie , Leroy Georges 
Published: December 2004

AbstractIn this work, we report an all‐electron SCF–LCGO–CO computation for the ground state wave‐function of an infinite polyenic chain. This work demonstrates that ab initio calculations on the electronic structure of polymers become actually feasible. Our results are compared with previously obtained semi‐empirical ones.
Intermolecular interactions in the region of small overlap
Authors: Basilevsky M. V. , Berenfeld M. M. 
Published: December 2004

AbstractIn order to treat the interaction energy of two molecules a standard Rayleigh‐Schrödinger perturbation theory is developed. The Hartree–Fock functions of the separated molecules are used as one particle basis functions, the initial set of states being truncated and non‐orthogonal. The non‐orthogonality is included into the Hamiltonian by orthogonalization of the basis set. The unperturbed Hamiltonian is chosen so that it possesses the correct symmetry properties with respect to the electron permutations between different molecules. The procedure of this kind automatically results in the appearance of charge transfer states.A graphical technique is elaborated which is a modified version of the Feynman–Goldstone technique and provides a convenient representation of the interaction energy contributions of any order. As an example the first‐ and the second‐order diagrams are considered.A correct expression for the dispersion energy is obtained which differs by a factor from that of the theory using a nonsymmetrical zero approximation.
On the theory of electron correlation in atoms and molecules. II. General cluster expansion theory and the general correlated wave functions method
Authors: Roby Keith R. 
Published: December 2004

AbstractAn exact cluster expansion of many electron wave functions is derived, beginning with a finite linear combination of Slater determinants rather than the more usual single determinant. This general cluster expansion is found to apply both in the case where all possible Slater determinants from a finite set of spin orbitals are included in the linear combination, and in the case where the number of determinants is restricted.The special properties of that finite linear combination of determinants closest to the exact wave function in the least squares sense are studied. These properties lead to the derivation of a general correlated wave functions method, illustrating again the close relationship between methods of this type and cluster expansion theory. Additional approximations, necessary for practical calculations, are set out.
Branch point singularities in the energy of the delta‐function model of one‐electron diatoms
Authors: Certain P. R. , Brown W. Byers 
Published: December 2004

AbstractTwo different perturbation series (the polarization expansion and a united‐atom expansion) of the ground state energy of the delta‐function model for one‐electron diatoms are studied and the radii of convergence are determined. For both expansions the singularity in the energy which limits the radius of convergence is a branch point with exponent one‐half. The physical significance of the branch point is that for particular values of the perturbation parameter, two different energy eigenvalues coalesce. The positions of the branch points are computed as a function of the internuclear separation R. For all values of R, both series converge for all physical values of the perturbation parameters. A lower bound to the radius of convergence of the polarization expansion has been computed previously by Claverie. It is proved in the present paper that the lower bound calculation is in fact an exact determination of the radius of convergence. The results of the model study are applied to real one‐electron diatoms to suggest the possible location of a branch point singularity in the energy of the ground state.
On the determination of radial electron–electron distribution functions
Authors: Benesch Robert 
Published: December 2004

AbstractThe problem of evaluating the radial electron–electron distribution function P0(r12) from the spin‐free 2‐particle density matrix P(2)(r1, r2Ir'1, r'2) is considered in detail. The analysis is first applied to 2‐electron S‐type functions built from l2 configurations. For the special case l = 0, the expression for P0(r12) reduces to the result obtained by Coulson and Neilson.For non‐spherically symmetric states of N‐electron atoms, the angular integrations are handled by a procedure used by Calais and Löwdin in their evaluation of atomic integrals containing functions of r12. Consideration is also given to the evaluation of necessary radial integrals.
Comparison of several expansions in the calculation of static electric dipole π polarizability of conjugated molecules by pertubation theory. The ground and the first excited singlet states
Authors: Matzke P. , Chacon O. , Sanhueza E. , Trsic M. 
Published: December 2004

AbstractGround and excited singlet state dipole electric π polarizabilities of a set of conjugated molecules are calculated. Second order perturbation theory is used in the Epstein–Nesbet and Möller–Plesset versions. Hückel and SCF‐LCAO‐MO are used alternatively as a basis. The Möller–Plesset–SCF–LCAO–MO calculation appears well related to experimental values.