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1Author    K. Ganesan, R. Damle, J. RamakrishnaRequires cookie*
 Title    Proton NMR Study of Molecular Dynamics in Hydrazinium Perchlorate  
 Abstract    The proton spin-lattice relaxation time T l (at 5.4, 10 and 15 MHz) and second moment M 2 (at 9.8 MHz) have been measured in hydrazinium Perchlorate (N 2 H 5 C10 4). The temperature depen-dence of T, shows two minima. The low temperature T, minimum has been explained in terms of NH 3 reorientation about the N N axis while the high temperature minimum is attributed to the exchange of protons within the NH 2 group (180° flip about the H-N-H bisectrix). The activation energies for NH 3 and NH : motions are found to be 20.5 kJ mol" 1 and 39.8 kJ mol" 1 , respectively. The second moment variation u ith temperature shows two transitions around 120 K and 210 K and has been discussed in terms of NH 3 /NH 2 motions. 
  Reference    Z. Naturforsch. 45a, 102—106 (1990); received October 17 1989 
  Published    1990 
  Keywords    NMR study, Molecular dynamics, Hydrazinium Perchlorate 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0102.pdf 
 Identifier    ZNA-1990-45a-0102 
 Volume    45 
2Author    S. Itoh, M. Konagai, K. TakahashiRequires cookie*
 Title      
 Abstract    The structural and dynamic properties of molten lithium iodide are investigated at two pressures (334 MPa at 784 K and 1054 MPa at 915 K), using molecular dynamics simulations with Born-Mayer-Huggins type pair potentials. On increasing the pressure, the local packing of the ions changes from tetrahedral to octahedral, the self-exchange velocity in the coordination shells decreases by a factor of 0.031, Du by a factor of 0.033 and D, by a factor of 0.021. M o le c u la r D y n a m ic s S tu d y o f M o lte n L ith iu m Io d id e 
  Reference    Z. Naturforsch. 46a, 155 (1991); received February 15 1990 
  Published    1991 
  Keywords    Molecular dynamics, Liquid structure, Lil, Lithium iodide, Pressure 
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 TEI-XML for    default:Reihe_A/46/ZNA-1991-46a-0155.pdf 
 Identifier    ZNA-1991-46a-0155 
 Volume    46 
3Author    B.V S Murthy, K. P. Ramesh, J. RamakrishnaRequires cookie*
 Title    Molecular Dynamics in Tetramethyl Ammonium Hexabromo Selenate [N(CH 3 ) 4 ] 2 SeBr 6 . A Proton NMR Study  
 Abstract    spin-lattice relaxation time Ti and second moment M 2 have been studied as a function of tem-perature over the temperature range 445 to 77 K. A discontinuous change in Ti at 365 K, in-dicates the presence of a phase transition, while the slope change at 152 K, is attributed to a change in the TMA ion dynamics from tumbling to torsion. The 7i results could be explained in terms of inequivalent TMA ions and their small angle torsional oscillations. A second moment (M 2) transition occurs around 160 K and is ascribed to the freezing of TMA tumbling and CH 3 reorientation. 
  Reference    Z. Naturforsch. 48a, 868—870 (1993); received February 22 1993 
  Published    1993 
  Keywords    Molecular dynamics, Second moment, NMR, Spin-lattice relaxation time 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0868.pdf 
 Identifier    ZNA-1993-48a-0868 
 Volume    48 
4Author    GlennH. Penner3, Baiyi Zhaoa, KennethR. Jeffrey0Requires cookie*
 Title      
 Abstract    The molecular dynamics of solid (CH3)3NBH3 is investigated by deuterium NMR spectroscopy. Variable temperature lineshape analyses yield activation energies of 27 + 3, 19 + 2, and 12.5 ± 2 kJ/mol for -CH3, -N(CH3)3 and -BH3 rotation, respectively. Analysis of the temperature depen­ dence of the spin-lattice relaxation times, Tt , gives activation energies of 33 + 3, 15 + 1.5, and 14 + 1.5 kJ/mol, respectively. Direct comparison of rotational exchange rates (from lineshape simu­ lations) an of rotational correlation times (from Tx analyses) for -N(CH3)3 and -BH3 rotation indicate that the two motions are correlated in solid (CH3)3NBH3 and together constitute a whole molecule reorientation about the N-B bond. This is supported by an internal rotational barrier of 18.0 kJ/mol for-BH3 rotation, obtained from ab initio molecular orbital calculations at the MP2/6-31G* level. 
  Reference    Z. Naturforsch. 50a, 81—89 (1995); received September 22 1994 
  Published    1995 
  Keywords    NMR spectroscopy, Molecular dynamics, NMR relaxation 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-0081.pdf 
 Identifier    ZNA-1995-50a-0081 
 Volume    50 
5Author    AxelA. Hoffab, HansH. Diebner, Gerold BaiercRequires cookie*
 Title      
 Abstract    Starting from an algorithm for continuous chaos control, a reversible control method based on mutual diffusive coupling of chemical reactors is developed. With sufficient coupling strength, the proposed mutual coupling leads to control even if both reactors are of similar size. The controlling and controlled reactor exchange their roles at a certain size ratio. Insufficient coupling can lead to a more complex dynamics than that of the uncoupled reactors. This method for control via reversible coupling of chemical reactors should be implementable on a purely microscopic level. R e v e rsib le C o n tr o l o f C h e m ic a l R e a c tio n S y s te m s 
  Reference    Z. Naturforsch. 50a, 1141—1146 (1995); received August 16 1995 
  Published    1995 
  Keywords    Chaos control, Diffusive coupling, Synchronization, Molecular dynamics 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-1141.pdf 
 Identifier    ZNA-1995-50a-1141 
 Volume    50 
6Author    Lucia Calucci, Claudia Forte, Marco Geppi, CarloAlberto VeraciniRequires cookie*
 Title    Dynamics of Liquid Crystals by Means of 2 H-NMR: a Comparison between 4,4'-bis(hexyloxy)azoxybenzene and the Derivative Pd(II) Complex AZPAC  
 Abstract    In the present work we report a molecular dynamics investigation of the two mesogens 4,4'-bis(hexyloxy)azoxybenzene (HL) and its Pd(II) acetylacetonate derivative Azpac in their nematic phases. Deuterium Zeeman and quadrupolar spin-lattice relaxation times have been measured at 46.04 MHz on two isotopomers of Azpac (Azpac-d 4 and Azpac-c/ 26 > deuteriated on the aromatic core and on the alkoxy chains, respectively) and on HL-d 4 , an isotopomer of HL partially deuteri-ated on the aromatic core, by means of the Wimperis pulse sequence. The spectral densities obtained from the measured relaxation times are discussed in terms of internal and overall molecular motions. A small step rotational diffusion model for the overall molecular motions, superimposed on a free rotational model for internal motions, allowed diffusion coefficients for molecular spinning and tumbling and for phenyl ring rotations to be derived for HL; the same models were used in describing the dynamics of Azpac. 
  Reference    Z. Naturforsch. 53a, 427—435 (1998); received October 31 1997 
  Published    1998 
  Keywords    Liquid Crystals, Deuterium Relaxation, Molecular Dynamics, Metallomesogens, NMR 
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 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0427.pdf 
 Identifier    ZNA-1998-53a-0427 
 Volume    53 
7Author    G. Vöhringer, J. RichterRequires cookie*
 Title    Molecular Dynamics Simulation of Molten Alkali Nitrates  
 Abstract    Molecular dynamics (MD) simulations have been performed for several pure alkali nitrate melts. Special attention was paid to the examination o f the interaction potential: macroscopic quantities like pressure were calculated and compared with real values. To improve the results the commonly used potential for alkali nitrates (Coulomb pair potential and Born-type repulsion) has been extended by a short-range-attraction term to meet the real behaviour o f the liquid. With these improved potentials, simulations of pure L iN 0 3, N a N 0 3, K N 0 3, and R b N 0 3 have been performed with special regard to the influence of size and mass o f the cations on the transport effects to show analogies to isotope effects. The calculated self diffusion coefficients (SDC) have been compared to results obtained with the NMR spin echo method. 
  Reference    Z. Naturforsch. 56a, 337—341 (2001); received April 2 2001 
  Published    2001 
  Keywords    Simulation, Molecular Dynamics, Interaction Potential, Alkali Nitrate, Melt 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0337.pdf 
 Identifier    ZNA-2001-56a-0337 
 Volume    56 
8Author    E. Bill1, N. Blaes2, K. F. Fischer3, U. G. Onser2, K. H. Pauly3, R. Preston2, F. Seel4, R. Staab4, A.X T Rautw Ein1Requires cookie*
 Title    Crystal Structure and Mössbauer Spectroscopic Investigation of the Low Temperature Molecular Dynamics of Hexa(2-ethylimidazole)iron(II) Hydridotetracarbonylferrate(-II)  
 Abstract    The title compound 1 was synthesized as reaction product of pentacarbonyl iron with 2-ethyl-imidazole. A Zerewitinoff-determination shows that we are rather dealing with hydrido-tetracar-bonylferrate(-II) than with tetracarbonylferrate(-I) as supposed in a preceding paper. A new crystal structure analysis of 1 was performed. With respect to [HFe(CO)4]~ we found that three CO groups are ordered with normal tetrahedral angles, while the fourth CO group shows statisti­ cal distribution over three sites (disordered sites). The temperature parameters of the disordered CO sites are considerably more anisotropic than those of the ordered CO sites. Experimental Mössbauer spectra have been recorded between 4.2 K and 288.7 K. 1 exhibits a Mössbauer pattern with two subspectra, one for each of the cations and the anions. The cation subspectrum reflects normal ferrous high-spin behavior, while the anion subspectrum shows peculiar anomalies around 200 K. On the basis of our X-ray structure results molecular orbital calculations have been performed with the aim of deriving electric field gradient tensors for the various stochastic substates of [HFe(CO)4]~. These tensors were then used within the frame on an analytical lineshape formula. It turns out that the statistical distribution of the fourth CO group over three sites is associated with a jump behavior, similar to trapped diffusion, of the CO group among the three sites and not with static disorder. The Fe atom follows this jumb behavior, however, its triangular displacement body with jump distance d ~ 0.30 Ä is considerably smaller than that of the CO group. 
  Reference    Z. Naturforsch. 39b, 333 (1984); eingegangen am 15. A u gu st/10. Oktober 1983 
  Published    1984 
  Keywords    Hydridotetracarbonylferrate, Crystallography, Mössbauer Spectra, Temperature Factors, Molecular Dynamics 
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 TEI-XML for    default:Reihe_B/39/ZNB-1984-39b-0333.pdf 
 Identifier    ZNB-1984-39b-0333 
 Volume    39 
9Author    Martin Jäger1, Paul Schuler1, HartmutB. Stegmann, Antal RockenbauerbRequires cookie*
 Title    Molecular Recognition Analyzed by Observing Intramolecular Interconversion with E PR Spectroscopy  
 Abstract    Molecular recognition between Rebek's cleft R and 4-(2-benzimidazolyl)-aminomethyl-2,6-di-rm-butyl-phenol (Bi) is investigated by means of EPR spectroscopy. Their specific inter-molecular interactions are distinguished from non-specific interactions represented by mere protonation on addition of benzoic acid. Both interactions are related to intramolecular in­ terconversions at the CQ-atom of Bi*, where a two-jump mechanism is found for free and protonated Bi* and a two-site exchange for the complexed ligand. While NMR spectroscopy indicates the existence of 1:1 and 1:2 receptor-substrate complexes, the faster time scale of EPR spectroscopy allows to identify one 1 : 2 as well as three 1 : 1 associates and to elucidate their formation conditions. Based upon the corresponding hf parameters, binding modes and sites are proposed for the key-in-the-lock system. 
  Reference    Z. Naturforsch. 53b, 1511—1519 (1998); received July 22 1998 
  Published    1998 
  Keywords    Rock-Key-Equilibria, Spin Labeling, Molecular Dynamics 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-1511.pdf 
 Identifier    ZNB-1998-53b-1511 
 Volume    53 
10Author    W. DrabowiczRequires cookie*
 Title    Molecular Dynamics Study of the Structural and Dynamical Properties of Liquid Tetrahydrofuran  
 Abstract    A molecular dynamics simulation has been performed to investigate the structural and dynamical properties of liquid tetrahydrofuran. In particular, we have calculated six radial distribution func-tions, translational and rotational autocorrelation functions and their associated frequency spectra. 
  Reference    Z. Naturforsch. 45a, 1342—1344 (1990); received January 16 1990 
  Published    1990 
  Keywords    Structural and dynamical properties, Molecular dynamics, Simulation, Tetrahydro-furan 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-1342.pdf 
 Identifier    ZNA-1990-45a-1342 
 Volume    45 
11Author    J. Jadżyn, G. Czechowski, B. Żywucki, C. Legrand, P. Bonnet, R. DąbrowskiRequires cookie*
 Title    Dielectric Properties of Mesomorphic n-TPEB's in Isotropic Phase  
 Abstract    Dielectric relaxation studies have been performed for the isotropic phase of a series of mesogenic molecules of l-[3-n-alkyl-biphenyl]-2-[4-isothiocyanatophenyl]ethane, CnH 2n+ 1 -(f)-(t>-CH 2 CH 2 -<p-NCS (n-TPEB), for n = 7, 8 and 9. Two Debye-type dielectric absorption bands have been interpreted as corresponding to the rotation around the short and long molecular axis. 
  Reference    Z. Naturforsch. 48a, 871—874 (1993); received May 29 1993 
  Published    1993 
  Keywords    Dielectric relaxation, Molecular dynamics, Mesomorphic molecules, Relaxation time, Activation energy 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0871.pdf 
 Identifier    ZNA-1993-48a-0871 
 Volume    48 
12Author    C. Cruz, J. L. Figueirinhas, P. J. Sebastião, A. C. Ribeiro, F. Noack, H. T. Nguyen, B. Heinrich, D. Guillon, I.P C MRequires cookie*
 Title    Molecular Dynamics in the Columnar and Lamellar Mesophases of a Liquid Crystal of Biforked Molecules  
 Abstract    In this work we present the first study of molecular dynamics in the S c and 4> h mesophases of a liquid crystal of biforked molecules. This study was performed by means of proton NMR relaxation measurements obtained at different temperatures in the studied phases, combining standard and fast field-cycling techniques in order to cover a large domain of Larmor frequencies (100 Hz-300 MHz). The experimental results were analysed considering the potential contributions of different relax-ation mechanisms, namely local molecular rotational reorientations, self-diffusion and collective movements. The description of the contributions of the rotational reorientations and self-diffusion mechanisms are not quite different in the two studied phases. The main distinction in the molecular dynamics is found in the low Larmor frequency range dominated by the collective movements. While in the S c phase this contribution can be described by the law characteristic of smectic layer undulations, the contribution of the collective movements in the </> h phase can be assigned to elastic deformation of the columns. 
  Reference    Z. Naturforsch. 51a, 155—166 (1996); received November 29 1995 
  Published    1996 
  Keywords    NMR, Proton Relaxation, Molecular Dynamics, Biforked Molecules, </> h Mesophase 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0155.pdf 
 Identifier    ZNA-1996-51a-0155 
 Volume    51 
13Author    Yoshihiro Okamoto, Toru OgawaRequires cookie*
 Title    Structure and Dynamic Properties of Molten Lanthanum Tribromide  
 Abstract    The structure of molten LaBr 3 was investigated by X-ray diffraction and molecular dynamics simu-lations. It was found that the short range structure of molten LaBr 3 is very similar to that of molten LaCl 3 , except for some structural features such as interionic distances based on the difference of anion sizes. In the MD simulation, the shear viscosity of molten LaBr 3 was estimated from the structurally-optimized MD calculations. 
  Reference    Z. Naturforsch. 54a, 91—94 (1999); received November 27 1998 
  Published    1999 
  Keywords    Molten Salt, Rare Earth Halide, X-ray Diffraction, Molecular Dynamics 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0091.pdf 
 Identifier    ZNA-1999-54a-0091 
 Volume    54 
14Author    Z. T. Lalowicz, S. F. SagnowskiRequires cookie*
 Title     
 Abstract    u ltia x ia l R e o r ie n ta tio n s o f N D ^ Io n s S tu d ie d b y 2 H -N M R S p e c tro s c o p y The density matrix formalism is used to simulate motional averaging in the 2H-NMR spectra of reorienting ND4 ions. The development of the spectra under increasing jump frequency about a single C3 or C2 axis is followed. Next we assume a hierarchy of axes in terms of activation energies sufficient to reach extreme narrowing conditions for some axes before activating jumps about a next one. Primary reorientations about the fastest C3 or C2 symmetry axes define the shape of spectra, the width of which is then stepwise reduced by fast reorientations about the subsequent axes in a postulated sequence of statistically uncorrelated jumps. 
  Reference    Z. Naturforsch. 46a, 829 (1991); received July 11 1991 
  Published    1991 
  Keywords    Deuteron NMR spectroscopy, Molecular dynamics, Ammonium salts, Ammonium ion reorientations -PACS number 7660 
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 TEI-XML for    default:Reihe_A/46/ZNA-1991-46a-0829.pdf 
 Identifier    ZNA-1991-46a-0829 
 Volume    46 
15Author    Keizo Horiuchi, Daiyu NakamuraRequires cookie*
 Title    Chlorine Nuclear Spin-Spin Relaxation Mechanism in Mg(H 2 0) 6 SnCl 6 as Studied by NQR and NMR Techniques  
 Abstract    The 35 C1 NQR spin-lattice relaxation time T1Q, spin-spin-relaxation time T2Q, and J H NMR spin-lattice relaxation time in the rotating frame T le in Mg(H20)6SnCl6 were measured as functions of temperature. Above room temperature T2q increased rapidly with increasing temperature, which can be explained by fluctuations of the local magnetic field at the chlorine nuclei due to cationic motions. From the T le experiments, these motions are found to be attributable to uniaxial and overall reorientations of [Mg(H20)6] 2+ ions with activation energies of 95 and 116 kJ mol -1 , respectively. Above ca. 350 K, T1Q decreased rapidly with increasing temperature, which indicates a reorientational motion of [SnCl6] 2-ions with an activation energy of 115 kJ mol -1 . 
  Reference    Z. Naturforsch. 47a, 277—282 (1992); received October 29 1991 
  Published    1992 
  Keywords    Complex compounds, Molecular dynamics, Nuclear relaxation, Nuclear quadrupole resonance, Nuclear magnetic resonance 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0277.pdf 
 Identifier    ZNA-1992-47a-0277 
 Volume    47 
16Author    Günter Burbach, Norbert Weiden, Alarich WeissRequires cookie*
 Title    Molecular Motions in Solid [Sb(CH 3 ) 4 ]PF 6 . A Combined 19 F Nuclear Magnetic Resonance and Quasielastic Neutron Scattering Study  
 Abstract    The molecular dynamics of tetramethylstibonium hexafluorophosphate, [Sb(CH 3) 4 ]PF 6 , is inves-tigated over a broad temperature range. NMR spin lattice relaxation times and the NMR second moments of the *H and F nuclei were determined in the range 8.6 < T/K ^ 332.3 for polycrystalline [Sb(CH 3) 4 ]PF 6 . The complex cation undergoes isotropic tumbling for T>260 K and thermally activated methyl group rotation in the temperature range T< 196 K. The activation energies for the transition from methyl group rotation to cation reorientation, as derived from NMR wideline (18.1 kJ/mol) and relaxation (22.7 kJ/mol) measurements, match. At very low temperatures pseudo classical line narrowing is observed, indicating tunneling motions of the methyl groups. The exis-tence of two crystallographically inequivalent methyl groups is found by X-ray structure analysis at room temperature. The space group is P6 3 mc, Z = 2; a = 738.6 pm, c = 1089.3 pm. It is confirmed by two steps in the temperature dependence of the signal intensity of the quasielastic line in neutron fixed window measurements in the temperature range 2 < T/K <148. The low temperature spin lattice relaxation times can be explained qualitatively by contributions of two crystallographically inequivalent methyl groups. Apparent activation energies for the two crystallographically different methyl groups are estimated. The complex anion undergoes isotropic tumbling in the temperature range 95 < T/K < 330. Above 330 K additionally translational motion is activated. Below 95 K the rotational motion of PF 6 e is freezing in via an uniaxial state in range 40 < T/K <80. Activation energies for both isotropical tumbling (10.5 kJ/mol) and uniaxial rotation (5.8 kJ/mol) have been derived from 19 F NMR spin lattice relaxation. 
  Reference    Z. Naturforsch. 47a, 689—701 (1992); received January 16 1992 
  Published    1992 
  Keywords    Complex compounds, Molecular dynamics, Rotational tunneling, Nuclear magnetic resonance spectroscopy, Quasielastic neutron scattering 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0689.pdf 
 Identifier    ZNA-1992-47a-0689 
 Volume    47 
17Author    Yoshihiro Okamoto, Torn OgawaRequires cookie*
 Title    Structure and Thermodynamic Properties of Molten Rare Earth-Alkali Chloride Mixtures  
 Abstract    The dependence of the enthalpy of mixing on the structure of molten rare earth-alkali chloride mixtures has been investigated by molecular dynamics simulation. The experimental enthalpy of the mixing with its negative and its dependence on the cation size was qualitatively reproduced. It became clear that the enthalpy of mixing depends on the structural features of short and medium range. 
  Reference    Z. Naturforsch. 54a, 599—604 (1999); received August 16 1999 
  Published    1999 
  Keywords    Molten Salt, Molecular Dynamics, Enthalpy of Mixing, Rare Earth-alkali Chloride Mixture 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0599.pdf 
 Identifier    ZNA-1999-54a-0599 
 Volume    54 
18Author    Takahiro Iijima, Motohiro Mizuno, Masahiko SuharaRequires cookie*
 Title    H NMR Study of Molecular and Electron Spin Dynamics in Paramagnetic [Co(H 2 0) 6 ][SiF 6 ]  
 Abstract    The temperature dependences of 2 H NMR spectra and the spin-lattice relaxation time T\ were measured for [Co(H20)f,][SiF6]. The variation of the spectrum above room temperature can be explained by the reorientation of [Co(H20)fi] 2+ about the C3 axis. The activation energy E a and the jumping rate at infinite temperature fco for the three site jump of [Co(H20)6] 2+ were obtained as 82 kJmol -1 and 2x 10 17 s~ 1 from the spectral simulation. Below room temperature, the spectral line shape was dominated by the 180° flip of the water molecule. The minimum of T\ caused by the 180° flip of the water molecule was observed at ca. 260 K. The jumping rate of the 180° flip of the water molecule was estimated from the 2 H NMR T\ and the spectral simulation. E* = 38 kJmol -1 and fco = 6x 10 l5 s -1 for the 180° flip of the water molecule were obtained from T\. 
  Reference    Z. Naturforsch. 55a, 173—177 (2000); received August 23 1999 
  Published    2000 
  Keywords    Phase Transition, 2 H NMR, Nuclear Quadrupole Interaction, Paramagnetic Shift, Molecular Dynamics 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0173.pdf 
 Identifier    ZNA-2000-55a-0173 
 Volume    55 
19Author    Motohiro Mizuno, Takahiro Iijima, Kengo Orii, Masahiko SuharaRequires cookie*
 Title    Water Molecular Motion and Hydrogen Bond in Paramagnetic [Cu(H 2 0) 6 ][PtCl 6 ] as Studied by Single Crystal 2 H NMR  
 Abstract    The temperature and angular dependences of the 2 H NMR spectrum were measured for single crystal [Cu(H 2 0) 6 ] [PtCl 6 ]. (e 2 Qq/h, r?) = (132 kHz, 0.72) were obtained for the D nucleus averaged by the fast 180° flip of the water molecule at 297 K. D,(236 kHz, 0.10) and D 2 (246 kHz, 0.09) were obtained for two unequal D nuclei of the water molecule at 133 K. Below T c , at least three nonequivalent waters were found to exist. The jumping rate for the 180° flip of the water molecule (k) was obtained from the simulation of 2 H NMR spectra at //o||[l 11] direction. The activation energy E d and the jumping rate at infinite temperature were estimated from the temperature dependence of k to be 24kJmol _1 and 1 x 10 13 s -1 . 
  Reference    Z. Naturforsch. 55a, 178—182 (2000); received August 23 1999 
  Published    2000 
  Keywords    Phase Transition, 2 H NMR, Nuclear Quadrupole Interaction, Paramagnetic Shift, Molecular Dynamics 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0178.pdf 
 Identifier    ZNA-2000-55a-0178 
 Volume    55 
20Author    HansH. DiebnerRequires cookie*
 Title    On the Entropy Flow between Parts of Multi-component Systems, Partial Entropies and the Implications for Observations  
 Abstract    The concept of the time dependent instantaneously occupied phase space volume is applied to multi-component systems. It allows for the investigation of entropy flows betweeen the components of the system and the evaluation of partial entropies assigned to the subsystems. We give numerical examples by means of molecular dynamics simulations of a 100-particle gas. Using a symplectic exactly reversible algorithm, a consistent and reliable evalutation of energy and entropy exchanges as well as the intake of work is achieved. The entropy flow which is related to an information flow is linked to an observational situation. This yields a further indication for the necessity of an intrinsic observer for a better understanding of the physical world. In addition, it indicates the Gödelian structure of cognition in a most serious way because only "first-principle" assumptions are made. Thereby, the paradoxical situation which is created by Jaynes' concept of an "anthropomorphic entropy" can be resolved by putting the anthropomorphic contents of thermodynamics down to an ontological basis. This is a straightforward extension of Szilard's and Brillouin's information theoretical treatment of cognition. 
  Reference    Z. Naturforsch. 55a, 405—411 (2000); received January 8 2000 
  Published    2000 
  Keywords    Information Flow, Intrinsic Observer, Phase Space Volume, Molecular Dynamics, Entropy Flow 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0405.pdf 
 Identifier    ZNA-2000-55a-0405 
 Volume    55 
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