Structure analysis and derivation of deformed electron density distribution of polydiacetylene giant single crystal by the combination of X-ray and neutron diffraction data

Tashiro, Koji*; Kusaka, Katsuhiro*; Hosoya, Takaaki*; Ohara, Takashi; Hanesaka, Makoto*; Yoshizawa, Yoshinori*; Yamamoto, Hiroko*; Niimura, Nobuo*; Tanaka, Ichiro*; Kurihara, Kazuo*; et al.

Macromolecules, 51(11), p.3911 - 3922, 2018/06

https://doi.org/10.1021/acs.macromol.8b00650

Accurate structure analyses of polymer crystals on the basis of wide-angle X-ray and neutron diffractions

Tashiro, Koji*; Hanesaka, Makoto*; Yamamoto, Hiroko*; Wasanasuk, K.*; Jayaratri, P.*; Yoshizawa, Yoshinori*; Tanaka, Ichiro*; Niimura, Nobuo*; Kusaka, Katsuhiro*; Hosoya, Takaaki*; et al.

Kobunshi Rombunshu, 71(11), p.508 - 526, 2014/11

https://doi.org/10.1295/koron.71.508

The crystal structure analysis of various polymer substances has been reviewed on the basis of wide-angle high-energy X-ray and neutron diffraction data. The progress in structural analytical techniques of polymer crystals have been reviewed at first. The structural models proposed so far were reinvestigated and new models have been proposed for various kinds of polymer crystals including polyethylene, poly(vinyl alcohol), poly(lactic acid) and its stereocomplex etc. The hydrogen atomic positions were also clarified by the quantitative analysis of wide-angle neutron diffraction data, from which the physical properties of polymer crystals have been evaluated theoretically. The bonded electron density distribution has been estimated for a polydiacetylene single crystal on the basis of the so-called X-N method or by the combination of structural information derived from X-ray and neutron diffraction data analysis. Some comments have been added about future developments in the field of structure-property relationship determination.

-dependence of spin exchange interactions in MnO ( = Rare-Earth Ions)

Kajimoto, Ryoichi; Mochizuki, Hidenori*; Yoshizawa, Hideki*; Shintani, Hiroshi*; Kimura, Tsuyoshi*; Tokura, Yoshinori*

Journal of the Physical Society of Japan, 74(9), p.2430 - 2433, 2005/09

https://doi.org/10.1143/JPSJ.74.2430

Magnon excitations have been investigated for PrMnO showing the -type antiferromagnetic ordering and TbMnO forming a long-period spin ordering by inelastic neutron scattering. Combined with a result of LaMnO [K.~Hirota ], the systematic data revealed that the ferromagnetic exchange interaction between nearest-neighbor (NN) Mn sites within the plane drastically decreases in MnO as the ionic radius of is reduced. In addition, finite next-nearest-neighbor (NNN) coupling is evident in TbMnO. In contrast, the exchange interaction along the axis shows much weaker dependence consistent with the Mn-O-Mn bond angle. These observations confirm a scenario that explains the evolution of spin structures in MnO in terms of the competition between the NN and NNN interactions [T.Kimura ].

Low energy magnetic excitation in TbMnO

Kajimoto, Ryoichi; Mitsui, Yukari*; Yoshizawa, Hideki*; Aso, Naofumi*; Shintani, Hiroshi*; Kimura, Tsuyoshi*; Tokura, Yoshinori*

no journal, , 

no abstracts in English

Magnetic structure of TbMnO studied by spherical polarimetry

Kajimoto, Ryoichi; Matsuda, Masaaki; Takeda, Masayasu; Kakurai, Kazuhisa; Mitsui, Yukari*; Yoshizawa, Hideki*; Kimura, Tsuyoshi*; Tokura, Yoshinori*

no journal, , 

no abstracts in English