NOPR Collection:

Nonlinear charge carriers in organic conjugated polymers

2017-03-20T11:43:07Z

Title: Nonlinear charge carriers in organic conjugated polymers Authors: Forner, Wolfgang Abstract: In this work a procedure for the prediction of the nature, stability, thermal behaviour and mobility of charge carriers in organic polymers exhibiting π conjugation is described on the basis of a simple semi-empirical n-electron model. These charge carriers are assumed to be charged solitons in polymers with degenerate ground state and charged polarons in those with non-degenerate ground state. On the basis of calculations on the dynamics of polyenes we explain in detail how the parameters of the model Hamiltonian can be determined. It is shown that energy levels in the gap due to the nonlinear quasiparticles can be calculated, at least qualitatively correctly, Further, a short review of simulations of the dynamics of the charge carriers in trans-polyacetylene is provided. For the first time we show theoretical spectra, calculated including electron correlations of negatively charged solitons in trans-polyacetylene (t-PA). Also for the first time an exact solution for the Su-Schrieffer-Heeger Hamiltonian is derived in the adiabatic limit, exhibiting explicitely the dynamics of the electrons. From the results obtained with this procedure the temperature dependence of the mobility of neutral solitons in t-PA is discussed, which is shown to start around 10K. while at 100K the solitons are found to be completely mobile in agreement with experiment. Further. for the first time the theoretical expressions are derived for the calculation of vibrational spectra from dynamic simulations. Finally it is shown how the procedure can be extended to other polymers, and how the stability of such polymers against oxygen can be studied with the help of more sophisticated methods. Page(s): 355-392

Interaction studies of simple carbohydrates in TBA-water and dioxane-water co-solvent mixtures

2017-03-20T11:36:34Z

Title: Interaction studies of simple carbohydrates in TBA-water and dioxane-water co-solvent mixtures Authors: Mishra, K; Puri, A K; Haroon, Shahla; Pandey, J D Abstract: Thermodynamic behaviour of simple carbohydrates has been measured in tertiary butyl alcohol (TBA)-water and dioxane-water co-solvent mixtures at 30°C. From the results, thermodynamic interaction coefficients, partial molal volume (Φ⁰_v), partial molal compressibility (Φ⁰_k), interaction coefficients (Q) and molar volume (V) have been calculated. That the same solute behaves differently in different solvents is clear from the results, which show that dioxane in organic solvent mixture acts as a structure breaker while TBA, in TBA-water co-solvent mixture enhances the three dimensional water mixture. Page(s): 393-396

High temperature reactions of boron oxide and nickel with copper (I and II) or silver oxide

2017-03-20T11:21:40Z

Title: High temperature reactions of boron oxide and nickel with copper (I and II) or silver oxide Authors: Tascioglu, Sulin; Akin, Zakir Abstract: The high temperature reactions between boron oxide and oxides of Cu(l), Cu(lI) and Ag(l) have been investigated in a nickel crucible at 1100°C in air. The ternary systems containing metallic nickel gave glassy products in two layers. Compositions of the fusion products have been determined by XRD, SEM, TEM, IR and chemical analyses and reaction pathways have also been elucidated.The reactions between CuO and B₂O₃ yield Cu₂Oand only Cu(l) borates, CuBO₂ or β -Cu₂B₄O₇ instead of CuO(II) borates, indicating predominant decomposition of CuO into CU₂O.The glasses obtained from Cu₂O and B₂O₃ give Cu(I) metaborate and the unexpected Cu(lI) metaborate CuO.B₂O₃ which can be decomposed to yield CU₂Oand CuBO₂. From the ternary Ag₂O-B₂O₃-Ni system, the only borates obtained are nickel borates . Nickel borates, unexpectedly rich in NiO content, 2NiO. B₂O₃ or 3NiO. B₂O₃, are observed in most glasses. Although the products do not show any significant electrical conductivity or magnetic properties, the hardness of material increases due to the presence of CuBO₂, β-Cu₂B₄O₇or CuB₂O₄ By controlling the reaction conditions the formation of such compounds can be ensured to obtain harder materials. Page(s): 397-405

Dioxomolybdenum(VI) complexes of bidentate and tetradentate Schiff bases derived from 3-methyl-1-phenyl-4-propionyl-2-pyrazolin-5-one and certain aromatic amines

2017-03-20T11:15:36Z

Title: Dioxomolybdenum(VI) complexes of bidentate and tetradentate Schiff bases derived from 3-methyl-1-phenyl-4-propionyl-2-pyrazolin-5-one and certain aromatic amines Authors: Maurya, R C; Jayaswal, M N; Verma, R Abstract: The synthesis of some cis-dioxomolybdenum(VI) complexes with bidentate and tetradentate ligands (I & II) derived from 3-methyl-l-phenyl-4-propionyl-2-pyrazolin-5-one and certain aromatic amines are described. The complexes are of the type [MoO₂(OEt)(L)]₂ (where LH = MPHPRP- OAH, MPHPRPMAH, MPHPRP-PAH, MPHPRP-OPH, MPHPRP-PPH, MPHPRP-OTH or MPHPRP-MTH), [MoO₂(MPHPRP-OPHD)], and [{MoO₂(OEt)}₂(L)] (where LH₂ =MPHPRP-MPHDH₂, MPHPRPPPHDH ₂ or MPHPRP-BZH₂). They are characterized by IR, electronic and magnetic studies. Page(s): 406-410