Structure molecular conformation

Additional instrumental techniques are now being used in conjunction with the traditional permeability experiments to probe the physical structures of the stratum corneum. These studies are contributing to the understanding of the molecular structure, conformation and order of the stratum corneum and its components. 

Volume 6 1.Hargittai Sulphone Molecular Structures. Conformation and Geometry from Electron Diffraction and Microwave Spectroscopy Structural Variations. 1978.40 figures. VII, 175 pages ISBN 3-540-08654-4... 

Ramanadham M, Chidambaram R (1978) Amino acids systematics of molecular structure, conformation and hydrogen bonding. In Srinivasan R (ed) Adv. Crystallogr., Invited Rev Lect Natl Conf Crystallogr 1977, Oxford and IBH, New Delhi, pp 81-103... 

Kym, P. R. Anstead, G. M. Pinney, K. G. Wilson, S. R. Katzenellenbogen, J. A. Molecular structures, conformational analysis, and preferential modes of binding of 3-aroyl-2-arylbenzo[b]thiophene estrogen receptor ligands LYl 17018 and aryl azide photoaffinity labeling analogs, J. Med. Chem. 1993, 36, 3910-3922. 

Here, in particular, the Cotton effect (CE) of the (n, n ) band of carbonyl compounds (around 280 nm) was of central importance For the establishment of the relationship between molecular structure (conformation) and the (n, n ) CE several rules with various theoretical backgrounds (and various levels of sophistication) are available ... 

The molecular mechanics method is used to calculate molecular structures, conformational energies, and other molecular properties using concepts from classical mechanics. Electrons are not explicitly included in the molecular mechanics method, which is justified on the basis of the Born-Oppenheimer approximation stating that the movements of electrons and the nuclei can be separated. Thus, the nuclei may be viewed as moving in an average electronic potential field, and the molecular mechanics method attempts to describe this field by its force field. ... 

H. Sun, Macromolecules, 26, 5924 (1993). Ab Initio Characterizations of Molecular Structures, Conformation Energies, and Hydrogen-Bonding Properties for Polyurethane Hard Segments. 

The rapid progress in correlating the molecular structure, conformation, supramolecular organisation and the chemical and physical properties of organic polymers, coupled to the continually improving capacity to model these things theoretically [16] continues to place heavy demands on the methods available for the precisely controlled synthesis of... 

Vibrational spectroscopy provides for the analysis of the chemical composition, molecular structures, conformations, and interactions in a sample. Two methods that are commonly used for molecular vibrational analysis are infrared (IR) and Raman spectroscopy. One of the limitations of the former, which relies on measuring the absorption or reflection of mid-IR radiation by molecular bonds, is the low spatial resolution afforded by the technique, allowing only chemical information from a large group of cells to be obtained. Raman spectroscopy, on the other hand, offers high spatial resolution subcellular chemical analysis of an individual cell. It relies on the scattering of photons by molecular bonds, which yields chemical information about the molecular stmcture and conformations in the sample. It has seen an increase in its use for biological studies because it offers many attractive features. The method is able to... 

Equations (8-13) and the associated parameters constitute a force field (see Force Fields A Brief Introduction and Force Fields A General Discussion). There are both all-atom and united-atom models the former have an interaction site i at the nucleus of each atom, while the latter retain the all-atom description except for hydrogens on saturated carbon, which are taken as implicit. The parameters for the most successful force fields for liquid simulations have been developed to yield simultaneously excellent descriptions of molecular structure, conformational energetics, intermolecular interaction energies, and properties of fluids including densities, heats of vaporization, and free energies of solvation (see OPLS Force Fields). 

Light absorption is not only characterized by energy and intensity, it also has directional properties. These are often overlooked, even when they might provide essential information. Such information includes assignments of electronic and vibrational transitions and information on molecular structure, conformation and association. The directional properties of individual molecules cannot be observed in isotropic samples but require samples that are non-isotropic or aligned. 

The spectral intensity varied from film to film prepared in repeated experiments. As an example, CD and absorption spectra of the three film samples prepared using the poly(PDBF) from run 2 in Table 5 are shown in Fig. 36. The films differed in thickness and roughness of the surface. A smoother film tended to show larger CD band intensities. Film surface morphologies of samples in Fig. 36A, C are shown in Fig. 37a, b, respectively. In most cases, the film surface showed a relatively regular, wrinkled pattern as shown in Fig. 37b. Such macroscopic morphologies might have a close connection to molecular structure (conformation) of the polymer in the film. 

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