bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyrrole aus einem 3‐Amino‐3‐arylazo‐propensäuremethylester und α‐Halogencarbonylverbindungen und die Bildung des Pyrrolo[3.2‐e][1,2,4]‐triazin‐Ringsystems
Authors: Kirschke Klaus , Costisella Burkhard , Ramm Matthias , Schulz Burkhard 
Published: December 2004

Pyrroles from Methyl 3‐Amino‐3‐arylazo‐propenoat and α‐Halogenocarbonyl Compounds and the Forming of the Pyrrolo[3.2‐e][1,2,4]‐triazin Ring SystemMethyl 3‐amino‐3‐(2,4,6‐trichlor‐phenylazo)propenoat (2) and α‐halogenocarbonyl compounds (4a–c) undergo cyclization to pyrroles on the pattern of the Hantzsch‐pyrrole‐synthesis. The 2‐(2,4,6‐trichlor‐phenylazo)‐3‐pyrrolecarboxylic azide (7) reacts under Curtius rearrangement and cyclization to the ring system of the pyrrolo[3.2‐e][1,2,4]‐triazin (8).
Synthese von Senföloxiden mit unterschiedlichen Substituenten
Authors: Tittelbach Franz 
Published: December 2004

Synthesis of Mustard Oil Oxides with Different SubstituentsTreatment of N‐alkyl‐N′‐aryl‐thioureas with chlorocarbonylsulfenyl chloride leads to 2‐alkyl‐4‐aryl‐3‐thiono‐1,2,4‐thiadiazolidin‐3‐ones (4). Isomerization of 4 takes place in the presence of strong acids to give 5‐alkylimino‐4‐aryl‐1,2,4‐dithiazolidin‐3‐ones (5). 5‐Arylimino‐4‐aryl‐1,2,4‐dithiazolidin‐3‐ones with different aromatic substituents (13a–e) are accessible by desulfurization of the corresponding 5‐arylimino‐4‐aryl‐1,2,4‐dithiazolidin‐3‐thiones (12) with benzonitril oxide. Structure of 4 follows both from desulfurization to the known 1,2,4‐thiadiazolidin‐3,5‐diones (9) and spectroscopic data.
3‐Alkylated (R)‐2,3‐Dihydroxyalkyl p‐Toluenesulfonates – homochiral building blocks for modified steroid side chains
Authors: Schrötter Eberhard , Luong Tran Thanh , Schick Hans 
Published: December 2004

AbstractOxidative cleavage of 1,2:5,6‐di‐0‐cyclohexylidene‐D‐mannitol (2) with lead (IV) acetate yields (R)‐2,3‐0‐cyclohexylideneglyceraldehyde, which was transformed by oxidation and esterification into methyl 2,3‐0‐cyclohexylideneglycerate. Grignard reaction with various alkylmagnesium halides followed by acid‐catalyzed removal of the acetal group and reaction with p‐toluenesulfonyl chloride in pyridine furnished the title compounds (8a–d) in good chemical overall yield and high enantiomeric purity. The compounds were prepared as intermediates for the synthesis of a series of steroids with a modified side chain.
Thiatriazole. VII. 3‐Aroxy‐5‐imino‐1,2,4‐dithiazole aus 5‐Amino‐1,2,3,4‐thiatriazol
Authors: Graubaum H. , Costisella B. , Ramm M. , Schulz D. 
Published: December 2004

Thiatriazoles. VII. 3‐Aroxy‐1,2,4‐dithiazole‐5‐imids of 5‐Amino‐1,2,3,4‐thiatriazoleThe unstable but isolable 3‐aroxy‐1,2,4‐dithiazole‐5‐imids (2a–d) has been found on chlorothioformate acylation of 5‐amino‐1,2,3,4‐thiatriazole (1) in acetonitril. Further acylation and nucleophilic displacement reactions gave stable 3‐amino‐5‐acylimino‐1,2,4‐dithiazoles (6a–c, 7). The structure of the prepared compounds was inferred from their 1H and 13C‐n.m.r., mass spectra and corroborated by comparison with the data of similar derivates as well as by chemical means.
Vibronic spectral behaviour of molecules. XV. Study on the T1 → S0 Phosphorescence of Isomeric Terphenyls
Authors: Gustav K. , Storch M. 
Published: December 2004

AbstractUnderlying the completely‐optimized S0 and T1 molecular geometries of isomeric terphenyls the corresponding theoretical vibronic T1 → S0 ‘line’ spectra calculated within the CONDON approach, are presented and compared with the experimental phosphorescences. The influence of possible conformations on the vibronic spectral behaviour is studied theoretically. The DUSHINSKY effect is found to be most important to the T1 → S0 phosphorescence of m‐terphenyl. An analysis of the spectroscopically relevant vibrational modes is given.
Zur Chemie der Mucohalogensäuren. V. Reaktionen von 3,4,5‐Trichlor‐2(5H)‐furanon und 3‐Aroxy‐4,5‐dichlor‐2(5H)‐furanonen mit Azid
Authors: Jähnisch Klaus , Ambrosi Horst‐Dieter 
Published: December 2004

Chemistry of Mucohalic Acids. V. Reaction of 3,4,5‐Trichloro‐2(5H)‐furanone and 3‐Aroxy‐4,5‐dichloro‐2(5H)‐furanones with Azide3,4,5‐Trichloro‐2(5H)‐furanone 1 reacts with sodium azide to afford 4‐azido‐3,5‐dichloro‐2(5H)‐furanone 2, whereas 3‐aroxy‐4,5‐dichloro‐2(5H)‐furanones 11 provides under the same conditions 3‐aroxy‐5‐azido‐4‐chloro‐2(5H)‐furanones 12. Reactions of 1 and 11 with two equivalents of azide lead to diazido derivatives 5 and 13. β‐Lactam 9 or pyrimidone 10 were synthesized from 5 and benzanilide.
A Formula for the Shaped Charge Jet Breakup‐Time
Authors: Hirsch E. 
Published: December 2004

AbstractIt was found that the breakup‐time of jets formed by shaped charges of cylindrical symmetry is given very accurately by the formula:

This formula is obtained from a general principal applied here for the first time which says that the breakup‐time of homogeneous ductile metals under very high strain rates is equal to the smallest initial dimension of the elongating metal divided by VPL. When applied to simple configurations such as a pipe which expands due to internal explosion this principal leads to a correct prediction of the average formed fragment dimensions. This principal provides for the first time an explanation to the experimental fact that metals' ductility can increase by an order of magnitude when the strain rate increases from 10−2 to 105 pro second.
On the Burning Rate Characteristics of CMDB Propellants
Authors: Swaminathan V. , Soosai Marian M. 
Published: December 2004

AbstractThe object of this paper is to obtain expressions for the burning rate pressure exponent and the temperature sensitivity of AP‐based and HMX‐based CMDB propellants in terms of the respective physical constants on the basis of a recently developed model of combustion for CMDB propellants and to examine the effects, if any, on these two parameters, of the changes in propellant composition, AP particle size and pressure. Computer programs were developed for this purpose and the results obtained for typical sets of input data presented in the paper. While the results of the calculation indicate a markedly strong dependence of the pressure exponent and the temperature sensitivity on pressure and composition for both AP‐based and HMX‐based CMDB propellants, the parameters are characterized by far lesser dependence on AP particle size for the AP‐based propellant.
Studies on the Synthesis of 2,2′,4,4′,6,6′‐Hexanitrostilbene
Authors: Golding P. , Hayes G. F. 
Published: December 2004

AbstractThe synthesis of 2,2′,4,4′,6,6′‐hexanitrostilbene by oxidative coupling of 2,4,6‐trinitrotoluene in the presence of metal catalysts has been studied. The effects of reaction parameters on product yields have been evaluated and mechanisms for the reaction are proposed.
Relation entre La Structure Electronique et la Sensibilité au Choc des Explosifs Secondaires Nitrés. Critère Moléculaire de Sensibilité II. Cas des esters nitriques
Authors: Delpuech A. , Cherville J. 
Published: December 2004

AbstractDans cet article, nous avons étendu aux esters nitriques l'étude de la relation entre structure électronique et sensibilité au choc, déjà effectuée sur les nitroaromatiques et les nitramines. On y vérifie la validité du critère moléculaire de sensibilité au choc précédemment établi. Ce travail permet, en outre, de proposer une échelle de sensibilité au choc englobant les explosifs organiques des primaires aux secondaires les moins sensibles.
EXTEST international study group for the Standardization of the Methods of Testing Explosives. (Formerly European commission for the standardization of the tests of explosives). Official report on the 8th meeting, EXTEST 78, held at Tatrânska Lomnica, Czechoslovakia, October 2–7, 1978
Authors: Persson P. A. 
Published: December 2004

AbstractThe present issue of “Propellants and Explosives” contains the Secretary's official report of the meeting, the individual Session and Working Group reports written by the session Chairmen, and the full texts of the technical papers presented and accepted for publication.The meeting discussed the following topics:

deflagration and transition from deflagration to detonation

initiation and stability of detonation of slurry and watergel explosives

sensitivity of slurry and watergel explosives

the underwater explosion test

testing of blasting fumes

test detonators

Steps towards standardization were taken in the field of deflagration and underwater explosion testing. There was also an exchange of views from different countries on the subject of methods of testing permissible explosives.
Sensibilité des bouillies
Authors: Michot C. , Bigourd J. 
Published: December 2004

AbstractDans les exploitations à ciel ouvert des mines et carrières, le chargement des cartouches en chute libre et le chargement de l'explosif en vrac par gravité dans les mines verticales sont réglementés en France par deux arrêtés. Le second arrêté s'applique aussi au chargement des bouillies en vrac par pompage.Les règles relatives aux conditions spéciales d'emploi s'appliquaient jusqu'à présent essentiellement aux explosifs nitrate‐fuel et aux premières bouillies expérimentées en France. Ces explosifs ayant une sensibilité faible, il suffisait d'en limiter l'aptitude à la détonation.Récemment sont apparues de nouvelles bouillies se distinguant des premières par une sensibilité plus grande ou par une aptitude à la détonation plus importante. Une révision des règles s'avérait par conséquent indispensable.Pour l'élaboration de nouvelles règles, il a été tenu compte des observations faites ces dernières années sur les bouillies et surtout des informations obtenues sur les explosions survenues en Amérique du Nord en 1975 et 1976, au pompage des bouillies. Ainsi, suivant les risques propes liés au mode de chargement et plus spécialement au matériel utilisé (pompe, appareil de chargement pneumatique), il est proposé de limiter la sensibilité de l'explosif d'autant plus que son aptitude à la détonation est importante. Les nouvelles règles élaborées ont été présentées à l'Administration compétente et sont maintenant en vigueur en France.
Studies on Curing of Polyurethane Propellant Binder System
Authors: Govindan G. , Athithan S. K. 
Published: December 2004

AbstractSolid propellant rocket technology makes use of polyurethane propellant system based on hydroxy terminated polybutadiene as binder. Processability of the propellant is determined by viscosity build‐up after unloading from the mixer, which in turn depends on rate of curing reaction between alcohols and isocyanate. For a typical binder system consisting of alcohols and isocyanate as in propellant composition, rate of curing has been studied using IR spectroscopy are carried out in solution phase. In this study, unaltered binder system was studied as such for the progress of the reaction as a function of time. Concurrently, viscosity studies were also carried out to study the rate of viscosity build‐up with time as reaction proceeds. With these studies two distinct phases have been brought out for the cure reaction of binder, first phase involving a linear reduction in concentration of the isocyanate groups followed by the second phase tending to equilibrium.
Conception, synthèse et caractérisation d'un nouvel explosif insensible et énergétique : Le DANTNP
Authors: Wartenberg Ch. , Charrue P. , Laval F. 
Published: December 2004

AbstractNous présentons dans cet article la stratégie de recherche développée pour la définition de mouvelles molécules explosives. L'application de notre déarche théorique à la conception d'un explosif insensible est illustrée par l'exemple du 5‐nitro‐4,6‐bis(5‐amino‐3‐nitro, 1H‐ 1,2,4‐triazole‐ 1‐y1)pyrimidine ou DANTNP. Le mode opératoire de synthése et les principales caractéristiques physico‐chimiques du matériau sont discutés. Le comportement expérimental de ce nouvel explosif est confronté aux prévisions issues de la méthodologie de conception.
On the extended method of calculation of atomic structures
Authors: Jucys Adolfas Pranaitis 
Published: December 2004

AbstractThe extended method of calculation of atomic structures is characterized. This method is understood as the use of as many radial orbitals as there are electrons in the atom under consideration. The process of passing from the ordinary method of calculation to the extended one is described. In the method proposed the additional complications appear within the confines of dealing with radial variables only. The general rules for carrying out the calculations, in applying the extended method, are formulated.
Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCFMOLC(LCGO) Methode. II. Das Benzol (C6H6)
Authors: Diercksen G. , Preuss H. 
Published: December 2004

AbstractDas C6H6 wurde im Gleichgewichtsabstand der Zentren unter Berücksichtigung aller 42 Elektronen ab initio mit dem Allgemeinen Programmsystem/SCFMOLC(LCGO) Methode berechnet. Es ergab sich eine Gesamtenergie von −227.27 a.E. und eine Ionisierungsenergie von 8.5 eV. Ferner wurde gefunden, dass den Einelektronen π‐Zuständen in energetischer Reihenfolge σ‐Zustände eingelagert sind.
Free‐electron model for the inelastic collision of fast electrons with benzene
Authors: Sen Purnendra Nath , Basu Sadhan 
Published: December 2004

AbstractUsing a free‐electron wave function the cross section for the excitation of the first excited state and that for the ionization of benzene in the inelastic collision with fast electrons have been estimated. In the ionization process the cross section has been found to be maximum when the secondary electron moves away with a kinetic energy of about 3 eV. For incident‐electron energy above 20 eV the cross section for ionization is larger than that for excitation, while below it the reverse is the case.
The polarization phenomena of spherical molecules
Authors: Boyle L. L. 
Published: December 2004

AbstractThe calculation of the polarizabilities of spherical molecules is discussed in the light of the average excitation energy approximation to perturbation theory. It is shown that whilst information about the energy in external fields can always be obtained from polarization phenomena, some information about the unperturbed wave function also can be obtained from magnetic susceptibility and Cotton–Mouton effect measurements. In the case of argon such information was found to agree with the results of self‐consistent‐field calculations. Predictions of the Cotton–Mouton constants of krypton and xenon are made.
Mechanism of photooxidation: Interpretation of the substituent effects in the photooxidation of acenic derivatives
Authors: Chalvet O. , Daudel R. , Ponce C. , Rigaudy J. 
Published: December 2004

AbstractIt has been observed that some substituents introduced in acenic derivatives are able to change the site of the fixation of oxygen during photooxidation. It is not possible to interpret this phenomenon by calculating the paralocalization energies. However, if an intermediate complex is introduced, which corresponds to an extension of the delocalized bond, a satisfactory explanation of the experimental results is possible.
The kinetic energy of molecular charge distributions and molecular stability
Authors: Bader R. F. W. , Preston H. J. T. 
Published: December 2004

AbstractThis paper examines the relationship between the topographical features of a molecular charge distribution and the kinetic energy of the system. Specifically, the spatial contributions to the kinetic energy are related to the Laplacian of the total charge density and to the gradients of the natural‐orbital densities. It is concluded that a necessary requirement for molecular stability is the existence of a net negative curvature for the molecular charge distribution in the internuclear region. It is shown that the charge density accumulated in the internuclear region of a stable molecule is distributed in such a way as to keep the accompanying increase in the kinetic energy to a minimum. A comparison of the contributions to the kinetic energy from the atomic and molecular charge distributions indicates that in the formation of a stable molecule the contribution from the molecular charge density in the binding region is decreased relative to that of the atoms.
Theorie quantique du pouvoir rotatoire magnetique des molecules diamagnetiques. I. Formalisme general
Authors: Smet P. 
Published: December 2004

AbstractThe quantum theory of the Faraday effect or magnetic rotatory power is set up for diamagnetic molecules and is based upon a variation‐perturbation method which, unlike the usual Dirac perturbation theory, needs only the knowledge of the wave function ψ of the ground state of the non‐perturbed molecule. The principle of this theory includes in the expression of the perturbed wave function, vectors which characterize the contribution of the different fields of perturbation. The quantities which descríbe the Faraday effect, obtained from the calculation of the electric and magnetic macroscopic dipole moments, are expressed from ψ and the vectors precedently introduced. They are determined by a variation calculus.
The calculation of matrix elements for valence bond functions
Authors: Shull Harrison 
Published: December 2004

AbstractPauling's formulas for the calculation of matrix elements for valence bond functions are derived using a simple substitutional process. The results generalize and simplify the formulas. In particular, the formulas do not depend upon orthogonality of atomic orbitals nor upon the nature of the choice of bond structures (canonical or not). The results are particularly adaptable to automatic computation.
LCAO–MO studies on hydrogen bonding: The interaction between carbonyl and hydroxyl groups
Authors: Schuster Peter 
Published: December 2004

AbstractPotential curves that show the energy dependence of hydrogen bonds between carbonyl and hydroxyl groups on the OH bond length, on the distance between the molecules, and on the angle between the functional groups have been calculated with the CNDO/2 method. The results are presented for a small model system–formaldehyde/water—and for the dimer of formic acid. Good agreement is obtained with the available experimental data. The influence of the molecular geometry on the calculated results is discussed.
Wellenmechanische untersuchungen am 2‐buten unter berücksichtigung aller elektronen
Authors: Janoschek R. , Preuss H. 
Published: December 2004

Abstract2‐butene has been investigated for different nuclear positions taking all 32 electrons into account, using the SCF–MO–LC(LCGO) method. The calculations show that the energy of the trans‐form is 1.1 kcal/mol lower than that of the cis‐form. The potential curve between these two forms is shown graphically. The ionization energy was estimated to be 9.0 eV.
Extended method of calculation for two shells of atomic electrons having the same orbital quantum number
Authors: Jucys A. P. , Našlenas E. P. 
Published: December 2004

AbstractAn extended method of calculation for two shells of atomic electrons, based upon the use of non‐orthogonal radial orbitals, is presented. The rules for going over from the radial integrals of the ordinary method of calculation to the linear combinations of radial integrals of the extended method of calculation are given. The numerical calculations are carried out for the ground states of lithium‐ and beryllium‐like atomic systems.
Theoretical study of isoelectronic systems: Diazomethane, ketene and allene
Authors: André J.‐M. , André M. Cl. , Leroy G. , Weiler J. 
Published: December 2004

AbstractAll‐electron SCF–LCAO–MO computations for diazomethane, ketene and allene are presented. The basis functions are contracted Gaussian orbitals. Theoretical results are discussed and related to available experimental data.
Increased‐valence formulae and the bonding of oxygen to haemoglobin
Authors: Harcourt R. D. 
Published: December 2004

AbstractThe molecular orbital configuration for the ground‐state of O2 generates the valence formula . “Increased‐valence” formulae for triatomic and polyatomic molecules have been developed recently. In them, more electrons participate in bonding than is possible for the familiar valence‐bond formulae. Using oxyhaemoglobin as an example of an oxygen carrier, various increased‐valence formulae are generated for the FeO2 groups. In the low‐energy formulae, the iron is bonded to the above valence formula for O2. Therefore, in contrast to the bonding schemes of Pauling and Coryell, Griffith and Weiss, little reorganization of O2 need occur on formation of HbO2. This conclusion is independent of the mode of co‐ordination of iron to the O2.
Self consistent molecular orbital calculations on polyatomic molecules: Gaussian approximation for two‐electron integrals
Authors: Bendazzoli G. L. , Bernardi F. , Palmieri P. 
Published: December 2004

AbstractA MO–LCAO–SCF treatment is performed on water, ammonia and methane using a recently proposed approximate method.The procedure is found capable of predicting total and orbital energies in close agreement with the results of accurate computations using double ζ basis sets of Slater type orbitals.A comparison is made with the results of similar approximate ab initio procedures.
On the complete set of functions in the Heitler–London method for two‐electron problem
Authors: Abarenkov I. V. 
Published: December 2004

AbstractIt is shown that under certain restrictions the system of determinants φi(x1)φk(x2) − φk(x1)ψi(x2) constructed from two different sets of orbitals ψk and φk will be the complete set of functions for antisymmetrical two‐electron wave functions if the condition i < k is imposed.
A change of variable for the perturbation parameter in rayleigh–Schrödinger perturbation theory
Authors: Amos A. T. 
Published: December 2004

AbstractThe Feenberg–Goldhammer change of scale, whereby the H0 in perturbation theory is replaced by (1/μ)H0 with μ a scaling parameter, is shown to be equivalent to a change of variable for the perturbation parameter. A more general change of variable is shown to lead to a perturbation series with perturbation energies E3, …, E2n+1 equal to zero. The resulting energy through (2n + 1)th order has the same form as that found from the Brillouin–Wigner series by different methods.
On the validity of Hamilton‐Jacobi mechanics in the mean in quantum mechanics
Authors: Taylor W. J. , Levine R. D. 
Published: December 2004

AbstractIt is shown that under certain conditions the time‐dependent Hamilton–Jacobi equation (TDHJE) is satisfied in the mean in quantum mechanics provided the classical action is replaced by Dirac's complex quantal action. This may be regarded as the equivalent of Ehrenfest's theorem for the TDHJE. Expectation values of operators are discussed in a similar manner.
The general theory of the extended method of calulation of atomic structures
Authors: Jucys A. P. , Naŝlėnas E. P. , Žvirblis P. S. 
Published: December 2004

AbstractA general theory of the extended method of calculation of atomic structures having complex configurations is presented. It is based on the correspondence between the radial integrals of the ordinary method and the linear combinations of those of the extended method. The rules for going over from the ordinary method to the extended one are given.
The spherical limit of H: A symmetry dilemma
Authors: Katriel J. 
Published: December 2004

AbstractThe spherical limit of H is studied as an example of the occurrence of a symmetry dilemma of a kind which is a general characteristic of truncated one centre expansions. At internuclear distances just somewhat larger than the equilibrium distance the best spherical approximation turns out to be centred off the molecular midpoint and is thus a mixture of σg and σu. Rather detailed insight into the situation is gained by an analysis based on the electrostatic Hellmann‐Feynman theorem.