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'Molecular dynamics' in keywords Facet   section ZfN Section A:Volume 055  [X]
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2000 (3)
1Author    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 
2Author    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 
3Author    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