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1993 (1)
1988 (1)
1Author    Zhengwei Su, Philip CoppensRequires cookie*
 Title    Electrostatic Properties of Molecules from the X-Ray Charge Density. Application to Deuterated Benzene, 1-Alanine and d,l-Histidine  
 Abstract    It has been shown (Z. Su and P. Coppens, Acta Cryst. A 48, 188 (1992)) that the electrostatic potential, the electric field, and the electric field gradient (EFG) can be expressed in closed forms in terms of the positions and the charge-density parameters of individual atoms, whose aspherical density is described by a pseudoatom model (e.g., N. Hansen and P. Coppens, Acta Cryst. A 34, 909 (1978)). A Fortran program Molprop91 based on this method has been written (Z. Su, State Univ. of New York at Buffalo 1991). The method has been applied to the title compounds. Low-temper-ature X-ray diffraction data of fully deuterated benzene (G. A. and d,/-histidine (N. Li, Ph.D. thesis, State University of New York at Buffalo 1989) were analyzed using the least-squares deformation density refinement program Lsmol90 (a modified version of Molly). Molprop91 was subsequently used to calculate the electrostatic-poten-tial maps in selected sections, and at the nuclear positions. For the latter, the EFGs were also evaluated. The electrostatic potentials were used to fit net atomic charges and estimate the molecular energies. Errors in the derived quantities are given. 
  Reference    Z. Naturforsch. 48a, 85—90 (1993); received April 23 1992 
  Published    1993 
  Keywords    Electron density, Electrostatic potential, Electric field, EFG, Molecular energy 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0085.pdf 
 Identifier    ZNA-1993-48a-0085 
 Volume    48 
2Author    H. WallschlägerRequires cookie*
 Abstract    o n lin e a r T h e r m o d y n a m ic s o f M o v in g M a te r ia l S u r fa c e s in E le c tric F ie ld s A continuum-mechanical formalism is presented for the phenomenological description of moving, curvilinear, material surfaces in electric fields in interaction with volume-phases. In addition to conventional equations (balance and constitutive laws) the explicit use of relations for the surface geometry is introduced. A method to establish nonlinear constitutive equations by tensorial and thermodynamical considerations is proved to be applicable to two-dimensional continua. The resulting equations for boundaries interacting with adjacent volumes are of practical importance for the selfconsistent calculation of boundary values. The physical meaning of the different relations is discussed. 
  Reference    Z. Naturforsch. 43a, 829—846 (1988); received April 13 1988 
  Published    1988 
  Keywords    A0340, A4700, A8265 Key words: Nonlinear irreversible thermodynamics, volume-surface-interaction, moving boundary, electric field 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0829.pdf 
 Identifier    ZNA-1988-43a-0829 
 Volume    43