bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dehydrierung 1‐substituierter Pyrazolidone‐(3) in Gegenwart von Formaldehyd und sekundären Aminen
Authors: Dorn Helmut , Otto Albrecht , Dilcher Herbert 
Published: January 2005

AbstractDie Dehydrierung der N‐MANNICH‐Derivate 2 1‐substituierter Pyrazolidone‐(3) ergibt C‐MANNICH‐Derivate 5 1‐substituierter 3‐Hydroxy‐pyrazole. Die Ausbeute an 5 ist quantitativ, wenn der 1‐Substituent Aryl ist und nimmt mit zunehmender Zahl der α‐H‐Atome im 1‐Substituenten ab. Als Nebenprodukte entstehen 1‐Alkyliden‐ bzw. 1‐Aralkyliden‐pyrazolidon‐(3)‐N1⊕,N2⊖‐betaine (Azomethinimine) 6. 5 erhält man auch direkt aus 1‐substituierten Pyrazolidonen‐(3), Formaldehyd, sekundären Aminen und Jod. NMR‐, IR‐Spektren und Reaktionsmechanismen werden diskutiert. 1‐Cyclohexylpyrazolidon‐(3) 1 b wird von Jod zu 3‐Hydroxy‐1‐cyclohexylpyrazol 3c und dem Azomethinimin 6c dehydriert, mit Brom entsteht außerdem 4‐Brom‐3‐hydroxy‐pyrazol 4c.
Über die Cyclisierung von 1,5‐Diacyl‐2‐alkyl‐diamino‐guanidinen und 1‐Acyl‐2‐alkyl‐5‐carbamoyl‐diaminoguanidinen zu 1,2,4‐Triazolen
Authors: Gehlen H. , Segeletz H. 
Published: January 2005

Abstract1,5‐Diacyl‐2‐alkyl‐diaminoguanidine 1 cyclisieren unter Wasserabspaltung zu 3‐(Nα‐Alkyl‐Nβ‐acylhydrazino)‐5‐aryl‐1,2,4‐triazolen 3. Die Cyclisierung der 1‐Acyl‐2‐alkyl‐5‐carbamoyldiaminoguanidine 2 führt zu 2‐Alkyl‐3‐[semicarbazido‐(1)]‐5‐aryl‐1,2,4‐triazolen 5. Aus 3 und 5 lassen sich durch Säurehydrolyse die entsprechenden Hydrazinotriazole 4 und 6 darstellen.
MO‐LCAO‐Berechnungen an Polymethinen. IV. Zum DÄHNEschen Konzept der gekoppelten Polymethine
Authors: Fabian J. , Tröger‐Naake G. 
Published: January 2005

AbstractAusgehend von einer quantenchemischen Charakterisierung des Polymethinzustandes, die in den vorangegangenen Arbeiten behandelt wurde, wird die Bedeutung der Streptopolymethin‐Teilsysteme für komplizierte molekulare Strukturen untersucht. Um die Elektronenstruktur des zusammengesetzten Systems mit denen der partizipierenden Teilsysteme zu vergleichen, werden die elektronischen Wellenfunktionen der Konfigurationsanalyse unterworfen. Die Lokalisierbarkeit in atomare und molekulare Subsysteme wird durch Indizes bewertet. Danach können zahlreiche Strukturen aus polymethinischen, polyenischen und aromatischen Fragmenten zusammengesetzt gedacht werden. Bei einigen carbo‐ und heterocyclischen π‐Systemen ist das Baukastensystem nur begrenzt anwendbar. Die Anwendungsbreite des Modells kann aber durch Anwendung der einfachen Störungstheorie 2. Ordnung leicht erkannt werden.
Darstellung und Eigenschaften von Pyrazolo[3,2‐c]benzo‐1,2,4‐triazinen und Pyrazolo[3,2‐c]pyrido[4,3‐e][1,2,4]triazinen
Authors: Hauptmann S. , Blattmann G. , Schindler W. 
Published: January 2005

Abstractα,β‐Ungesättigte β‐Aminonitrile 1 kondensieren mit 2‐Nitrophenylhydra‐zin und mit 4‐Hydrazino‐3‐nitropyridin zu Hydrazonen von β‐Ketosäurenitrilen 2 bzw. 3. Diese Verbindungen cyclisieren bei der Einwirkung von Basen zu Pyrazolo[3,2‐c]benzo‐1,2,4‐triazin‐5‐oxiden 7 bzw. Pyrazolo[3,2‐c]pyrido[4,3‐e] [1,2,4]triazin‐5‐oxiden 8. Die N‐Oxide lassen sich mittels Natriumdithionit zu den entsprechenden Triazinen 9, 10 reduzieren.
Zur Auswertung von UV‐Vis‐Spektren schwacher organischer π‐π‐Molekülkomplexe. X Die Beeinflussung der spektroskopischen und thermo‐dynamischen Charakteristika der Komplexbildung bei sterischer Hinderung
Authors: Bendig J. , Kreysig D. , Templer G. 
Published: January 2005

AbstractFür die TCNQ‐Komplexe des Anthracens sowie dessen 9‐Methyl‐, 9,10‐Dimethyl‐, 9‐Phenyl‐ und 9,10‐Diphenylderivate wurden die Assoziationskonstanten, Komplex‐bildungsenthalpien und ‐entropien bestimmt. Es zeigt sich eine Abnahme der Komplexbildungs‐fähigkeit bei zunehmender Phenylsubstitution, hervorgerufen durch eine sterische Hinderung der Komplexbildung. Letzteres führt zu größeren Werten für die Reaktionsentropie und infolge größerer Gleichgewichtsabstände zu kleineren Bildungsenthalpien im Vergleich zum Anthracen/TCNQ‐Komplex. Die erhaltenen Ergebnisse für die Molekülkomplexe im Grundzustand stehen in Einklang mit der Fähigkeit der Donatoren zur Photodimerisierung.
Mononuclear Benzoylhydrazide Complexes of Cu2+, Fe3+ and V5+O and Fe2+ sulphate. Single crystal X‐ray and E.P.R. data of the Cu2+ complex
Authors: Iskander George M. , Salama Salama B. , Osman Abdel Rahaman H. , Gulta Eman L. , Schlemper Elmer O. 
Published: January 2005

AbstractBenzoyl hydrazide monoligand complexes [M(BzH)]n+, where M = Cu2+, Fe2+, Fe3+ and V5+O are prepared and their physical data reported. X‐ray single crystal diffraction of Cu(BzH)CI2 reveal a nearly square planar configuration around the Cu2+; the benzoyl hydrazide molecule acting as a bidentate ligand with the CO and NH2 groups as coordinate sites and the partial contribution of the chloride ions as well. E.p.r. showed a low spin orbital coupling (500 cm−1) versus 830 cm−1 for the free Cu2+ ion; obviously coordinate bond chelation for the Cu2+ ion is envisaged.
(1S,2S)‐2‐Amino‐1‐aryl‐propane‐1,3‐diols as convenient educts for the Synthesis of Homochiral (S,S)‐Norpseudoephedrine
Authors: Boerner Armin , Krause Hanswalter 
Published: January 2005

AbstractA convenient high yield synthesis of homochiral norpseudoephedrine starting from waste products of the chloramphenicol synthesis is described as an example of its utilization in chemical transformations.
Studies on the reaction of o‐benzoquinone dioxime with aldehydes: An improved procedure for 1‐Hydroxybenzimidazole 3‐Oxides
Authors: Pätzold F. , Niclas H.‐J. , Gründemann E. 
Published: January 2005

AbstractAn improved method for the preparation of the title compounds 4 is described. Thus, 1‐hydroxybenzimidazole 3‐oxides are obtained in high yields by the reaction of o‐benzoquinone dioxime 1 with aromatic and heteroaromatic substituted aldehydes 2 in the presence of an excess of strong acids. The primarily formed salts 3 are transformed into 4 by neutralization. The reaction is assumed to proceed via the nitroso‐nitrone 6 as intermediate.
Synthese von Benzylidenaminopyrazolen und Bispyrazolopyridinen
Authors: Hennig L. , Hofmann J. , Alva‐Astudillo M. , Mann G. 
Published: January 2005

Synthesis of Benzylideneaminopyrazoles and Bispyrazolopyridines5‐Aminopyrazoles 1a–e react with aromatic aldehydes in boiling ethanol to yield azomethines 2a–n. Bispyrazolopyridines 7a–f are obtained by the reaction of 2a–f with an excess of aminopyrazole at higher temperatures via bisaminopyrazoles 5 and bispyrazolodihydropyridines 6. Structure and configuration of the products are assigned by n.m.r.‐spectroscopy. Reactions with replacement of the arylidene group on azomethine 2b suggest that the transformation of azomethines to bisaminopyrazoles occurs through a mechanism involving addition of the CH‐acidic component, with subsequent elimination of aminopyrazole.
Synthese, koordinationschemische und massenspektrometrische Charakterisierung neuartiger carboxylsubstituierter N‐(Thiocarbamoyl)‐benzamidine
Authors: Hartung J. , Weber G. , Beyer L. , Kirmse K. , Stach J. 
Published: January 2005

Synthesis, Coordination Chemistry and Mass Spectrometric Fragmentation of New N‐(Thiocarbamoyl)‐benzamidinesSyntheses of N‐(thiocarbamoyl)benzamidines from benzimidoylchlorides and aromatic amino acids as starting materials are reported. The prepared compounds were used as ligands for complexing nickel(II) and copper(II)ions. The benzamidines were characterized by mass spectrometric methods. The fragmentation pattern of the benzamidines was derived from the corresponding MIKE‐spectra.
Kinetische Untersuchungen zur Radikalisch induzierten Fragmentierung von Orthoformiaten des 2,2,3,3,4,4,5,5‐Octafluorpentan‐1‐ols
Authors: Gizatullina S. R. , Jakupov I. S. , Germač A. V. , Zlotskij S. S. , Rachmankulov D. L. , Timpe H.‐J. 
Published: January 2005

Kinetical Investigations on Radical Initiated Fragmentation of Orthoformiates of 2,2,3,3,4,4,5,5‐Octafluoropentan‐1‐oltert.‐Butoxy radicals abstract the methin hydrogen atom on orthoesters 1 of 2,3,3,4,4,5,5‐octafluoropentan‐1‐ol, and the radicals 2 thus formed fragmente at 130°C into dialkylcarbonates 3. Due to their acceptor properties the fluoroalkyl substituents influence the velocity of the hydrogen abstraction reaction. On the contrary, no influence of these substituents on the rate of the fragmentation step has been measured. With 2‐fluoroalkyl substituted 1,3‐dioxolanes the radical induced fragmentation leads to ring‐opened carbonates, which are the major products, and ethylene carbonate.
Zur Elektrochemie von 2‐Trichlormethyl‐tetrahydrofuranen
Authors: Fechtel U. , Westphal K. , Matschiner H. 
Published: January 2005

Electrochemistry of 2‐Trichloromethyl‐tetrahydrofurans4‐Alkoxy‐2‐trichloromethyl‐4‐methyl‐tetrahydrofurans (2) were prepared by anodic oxidation of 1,1,1‐trichloro‐4‐methyl‐pent‐4‐en‐2‐ol (1) in presence of bromide ions and bases. Electroreductions of these compounds in LiCl/Methanol lead to 2‐dichloromethyl‐tetrahydrofurans (6). Under acidic conditions an olefin (10) was formed as main product.
Kinetische Untersuchungen zur Reaktion von Methylradikalen mit But‐2‐in
Authors: Claus P. , Marquardt M. , Trung Tran Kim , Scherzer K. 
Published: January 2005

Kinetic Investigation of the Reactions of Methyl Radicals with But‐2‐yneThe reactions of methyl radicals with but‐2‐yne have been studied in a greaseless static vessel in the temperature range 543 ⃛583 K. The methyl radicals were generated by thermolysis of azomethane (initial pressures 2.66 kPa and 3.19 kPa) in mixtures with the alkyne (initial pressures 0 ⃛7,8 kPa). The primary steps are H‐abstractions producing 3‐methylpropargyl radicals and additions to the triple bond forming trimethylvinyl radicals. Both radicals were stabilized by hydrogen abstraction from the parent compounds and by combination processes. The temperature dependence of the rate constant k2 for the addition reaction can be expressed by the equation k2 = 108.65±0.20exp (−40300 ± 1300)Jmol−1/RT M−1 s−1 For the rate constant k1 of hydrogen abstraction a value of k1 = 1,65 · 105M−1 s−1 at 573 K was estimated. Therefore the H‐abstraction proceeds about two times faster than the addition reaction.
2‐Dialkylamino‐thiazolin‐4‐one aus α‐Thiocyanato‐carbonsäurederivaten
Authors: Zimmermann T. , Fischer G. W. , Olk B. 
Published: January 2005

2‐Dialkylamino‐thiazolin‐4‐ones from α‐Thiocyanato‐carboxylic Acid Derivativesα‐Thiocyanato‐acetic acid esters 1a‐c or amide 1d react with dialkylamine salts of weak acids to give 2‐dialkylamino‐thiazolin‐4‐ones 2a‐f. The reaction can be performed using aliphatic alcohols, dipolar aprotic solvents or halogenated hydrocarbons as reaction medium or by heating the educts at 90°C without any solvent. According to the latter method, the 5‐substituted thiazolinones 2g, h are obtained from α‐thiocyanatopropionic acid ethyl ester (1d) or α‐thiocyanato‐phenylacetic acid ethyl ester (1e) and dimethylamine acetate. ‐ I.r., u.v. and n.m.r. data of the thiazolinones 2 are reported.
Push‐pull‐Butadiene. XI. Darstellung und Reaktionen von Methylsulfonylnicotinonitrilen
Authors: Peseke K. , Schönhusen U. 
Published: January 2005

Push‐pull‐Butadienes. XI. Syntheses and Reactions of MethylsulfonylnicotinonitrilesMethylthionicotinonitriles 1, 3, 5, 9 and 12 react with potassium permanganate to give corresponding methylsulfonylnicotinonitriles 2, 4, 6, 10 and 13, respectively. Compounds 2 can be converted with sodium ethoxide to yield diethoxynicotinonitriles 7. Similarly 4, 5 and 6 react with sodium ethoxide to give 4‐aryl‐5‐bromo‐2,6‐diethoxy‐nicotinonitriles 8. Treatment of nicotinonitriles 9, 10 or 13 with sodium ethoxide gives diethoxynicotinonitriles 11. 2 with hydrazine hydrate together afford pyrazolo[3,4‐b]pyridines 14. However, an excess of hydrazine hydrate and 2 or 6 yields hydrazinopyrazolo[3,4‐b]pyridines 15.
Substituierte N,N′‐Bis(thiazol‐2‐yl)‐diaminoalkane aus α‐Thiocyanato‐acetophenonen und N,N′‐Dialkyl‐diamino‐alkanen
Authors: Zimmermann T. , Fischer G. W. , Teller J. , Dehne H. , Olk B. 
Published: January 2005

Substituted N,N′‐Bis(thiazol‐2‐yl)‐diaminoalkanes from α‐Thiocyanato‐acetophenones and N,N′‐Dialkyl‐diaminoalkanesα‐Thiocyanato‐acetophenones 1 react with N,N′‐dialkyl‐diaminoalkanes 2 in the presence of an appropriate weak acid (acetic acid, propionic acid, benzoic acid) to give the hitherto unknown N,N′‐dialkyl‐N,N′‐bis(4‐aryl‐thiazol‐2‐yl)‐diaminoalkanes 3. As reaction medium aliphatic alcohols (ethanol, methanol), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) or dipolar‐aprotic solvents (acetonitrile, dimethylformamide) can be used. ‐ I.r., u.v., n.m.r. and mass spectroscopic data of the novel bisthiazoles 3 are reported.
Zerfall von 1‐n‐Butylaminocyclohexyl‐phosphonsäure‐di‐n‐butylester (Buminafos) in wäßrigem Medium
Authors: Schneider B. , Porzel A. , Weidhase R. , Schütte H. R. 
Published: January 2005

Degradation of n‐Butylaminocyclohexyl phosphonic Acid di‐n‐Butylester (Buminafos) in Aqueous Medium.In aqueous medium, breakdown of Buminafos (1) is connected with total loss of its herbicidal activity. The phosphorus‐carbon bond is cleaved and n‐butylcyclohexylidene amine (3), cyclohexanone (5), phosphoric acid mono‐n‐butyl ester (4) (partly as n‐butylamine salt), and 1‐aminocyclohexyl phosphonic acid di‐n‐butylester (8) were found as degradation products of carbon‐14 labeled Buminafos. Identification was performed by MS, GC/MS, 1H‐ and 31P‐n.m.r. spectroscopy, by detection of phosphorus, and by means of the radioactivity.
Synthese und Dimroth‐Umlagerung von disubstituierten 5‐Imino‐1,2,4‐dithiazolidin‐3‐thionen (Senfölsulfiden)
Authors: Tittelbach Franz 
Published: January 2005

Synthesis and Dimroth Isomerization of Disubstituted 5‐Imino‐1,2,4‐dithiazolidine‐3‐thiones (Mustard Oil Sulfides).Treatment of N‐substituted dithiocarbamates with N‐substituted S‐chloroisothiocarbamoyl chlorides leads to disubstituted 5‐imino‐1,2,4‐dithiazolidine‐3‐thiones. Educts with different aromatic substituents give the diaryl derivatives 5, as expected by the reaction equation. Educts with one aromatic and one aliphatic substituent give 5‐alkylimino‐4‐aryl derivatives 10, regardless which starting component (3, 4, 7, 8) possesses the aliphatic or aromatic substituent. Educts with different aliphatic substituents (7, 8) leads to mixtures of isomeric derivatives 12, 13. Disubstituted 5‐imino‐1,2,4‐dithiazolidine‐3‐thiones with 5‐alkylimino group are able for Dimroth isomerization to 4‐substituted 2‐alkyl‐1,2,4‐thiadiazolidine‐3,5‐dithiones.
Developing a sound basis for the design of vented explosion barricades in chemical processes
Authors: Herrmann David D. 
Published: January 2005

AbstractMost commonly used barricade design methods are based on taking an explosion scenario and treating it as a “TNT equivalent.” A widely used approach in the chemical industry is documented in TM5‐1300. Although this may be a reasonable approach for explosives in cubical barricades, it may not always relate well to the reality of many chemical facilities. This paper discusses some of the limitations of the TM5‐1300 method, the need for a good definition of the hazardous event(s), and the use of computational fluid dynamics to define blast loads for barricade design. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Automation vs. Human intervention: What is the best fit for the best performance?
Authors: Haight Joel M. , Kecojevic Vladislav 
Published: January 2005

AbstractIn today's complex industrial processes, automated control systems are a necessity. However, is complete automation the answer? Whereas control system automation provides predictable, consistent performance, it is lacking in human judgment, adaptability, and logic. Although humans provide these, we are unpredictable, inconsistent, and subject to emotions and motivation. To maximize system performance, should we automate humans out of the system? … or … Do we maximize human input and lose efficient, consistent, error‐free system performance? The answer is likely somewhere in the middle of these two extremes and different for each system and situation. This paper provides a review of the existing literature covering control schemes and parameters that determine system performance. It attempts to help answer the questions “How can we minimize human error while still maximizing system performance?” and “What is the right human–machine mix?” © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Poole–Frenkel effect in Er doped SnO2 thin films deposited by sol‐gel‐dip‐coating
Authors: Morais Evandro A. , Scalvi Luis V. A. , Ribeiro Sidney J. L. , Geraldo Viviany 
Published: January 2005

AbstractElectrical properties of Er‐doped SnO2 thin films obtained by sol‐gel‐dip‐coating technique were measured. When compared to undoped tin dioxide, rare‐earth doped films present much higher resistivity, indicating that Er3+ presents an acceptor–like character into the matrix, which leads to a high degree of electric charge compensation. Current–voltage characteristics, measured above room temperature for Er‐doped films, lead to non‐linear behavior and two conduction regimes. In the lower electric field range the conduction is dominated by Schottky emission over the grain boundary potential barrier, which presents an average value of 0.85 eV. Increasing the applied bias, a second regime of conduction is observed, since the Poole–Frenkel coulombic barrier lowering becomes a significant effect. The obtained activation energy for ionization is 0.67 eV. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The double modulation superstructure of the room temperature stable phase of stoichiometric Cu2Te
Authors: Vouroutzis N. , Frangis N. , Manolikas C. 
Published: January 2005

AbstractThe structure of the room temperature phase αI‐Cu2Te is studied by means of electron diffraction and high resolution electron microscopy. It is found that the structure is the result of two modulations. The first one is the periodic introduction of planar translation interfaces perpendicular to the [111]c direction of the fcc basic structure. The second one is the ordering of Cu in octahedral and tetrahedral sites, in a way similar to that known for the β‐Cu2Se structure. The superstructure unit cell includes twelve Te layers. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scintillation mechanisms in Ce3+ doped halide scintillators
Authors: Dorenbos Pieter 
Published: January 2005

AbstractLast couple of years witnessed the development of various new Ce3+ doped halide scintillators (LaCl3, LaBr3, LuI3, Cs2LiYCl6, Cs2LiYBr6) that possess excellent gamma ray or thermal neutron detection properties. The scintillation pulse in LaBr3:Ce3+ is 20 times faster than in the most commonly used scintillator NaI:Tl. This, combined with a more then two times better energy resolution and higher gamma ray stopping power, makes it ideally suited for many different applications. In this work the scintillation properties and mechanisms of Ce3+ doped inorganic halide (Cl, Br, I) compounds are reviewed; especially the role of Vk centers and self trapped excitons (STEs) in the energy transfer from the ionization track to Ce3+ is treated. Aspects of the lifetime and thermal stability of the self trapped exciton, the migration speed of Vk centers and STEs, spectral overlap between STE emission and Ce3+ absorption, and the influence of the type of anion (Cl, Br, I) are addressed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multifrequency spectroscopy of defects in complex oxides
Authors: Malovichko G. , Grachev V. , Schirmer O. F. 
Published: January 2005

AbstractThe typical output of the one‐frequency methods is an image with a space resolution of the order of the used wavelength. Such images contain direct evidence about the space structure of a lattice or macroscopic defects; however, they are not very helpful for the study of the internal structure of the atomic‐size defects. Measurements which use sweeping of electromagnetic wave frequency or sweeping of an external parameter furnish spectra or dependencies of measured characteristics on the swept quantity. The spectra contain indispensable information about energetic characteristics of interactions of intrinsic and extrinsic defects with the lattice ions. Different frequencies in very wide region have to be used for the study of these interactions (multifrequency spectroscopy). An application of this new approach to defects in lithium niobate allowed to determine characteristics of various interactions with magnitudes from 104 to 1016 Hz, and to correlate them with definite models of the defects. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Creation of groups of spatially correlated excitations in wide‐gap solids
Authors: Kirm Marco , Lushchik Aleksandr , Lushchik Cheslav 
Published: January 2005

AbstractProcesses of efficient creation of groups of electronic excitations (EEs) or defects have been considered for radiation‐sensitive (alkali halides) and radiation‐resistant (metal oxides) single crystals. In MgO, pure or doped with Be2+, Ca2+ and Al3+ ions, the 7.63 eV edge emission of anion excitons is efficiently excited at 10 K in a wide region of 30–90 eV. Multiplication process with the creation of secondary electron–hole pairs and the decay process of cation excitations are compared in crystals of two types: (i) KCl, KBr and LiF, where anion excitons and valence holes undergo self‐trapping and (ii) a MgO crystal, where no self‐trapping of excitations occurs. In alkali halides, a group of spatially correlated EEs, formed at photon absorption, is transformed into an F–I–VK triplet of defects at 5 K or into a temperature‐stable F centre and a trihalide molecule (e.g., Br3–) at 295 K. In BaMgAl10O17:Eu at 295 K, the 2.72 eV emission of Eu2+ centres with quantum yield of 1.1–3.5 at the excitation by photons of 13–30 eV has been obtained. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocation induced absorption in silver halides
Authors: Kondo Y. 
Published: January 2005

AbstractInfrared absorption spectra of shallow electron centres in plastically deformed silver halide crystals are measured. The spectra consist of a sharp peak due to the isolated centres and a broad peak which shows splitting that may be due to the symmetry lowering along the dislocation edge, indicating some of the shallow electron centres are trapped on the dislocation lines. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simplification of point group projection operators and its application to symmetry adaptation of multishell electron configurations
Authors: Taijin Zhou 
Published: January 2005

AbstractA practical method for generating irreducible matrix reps of point groups and a concise formula about projection operators are proposed. By using this formula as well as versatile classification schemes, the symmetry adaptation of a many‐electron system is simplified. A unified algorithm and program of symmetry adaptation of spin‐free space have been developed.
Application of the recursion method to the study of the end effects on the bond length alternation in polyacetylene
Authors: Suzuki Masato , Imamura Akira 
Published: January 2005

AbstractWe describe how the local equilibrium electronic structure in a large system can be determined by using the recursion method of Haydock. By applying this method to the polyacetylene molecule, the energies of each atomic site and the forces acting on each bond are estimated and the equilibrium structure near the end of polyacetylene is determined. It is found out that the degree of localization of π electrons and the bond length alternation become stronger near the end of the polyacetylene molecule.
Contraction operator over electronic fock space. II. Weak representability problem
Authors: Panin A. I. 
Published: January 2005

AbstractTwo approaches in treating the weak representability problem for density operators are studied. In the first approach this problem is reduced to the minimization of a certain distance function. The second approach is based on inductive generation of linear inequalities for diagonal elements of the second‐order density operators. Generalization of Kuhn–Yoseloff's results is also discussed.