Dichroism in Helicoidal Crystals.
Dichroism in Helicoidal Crystals.
复制标题
DOI：
10.1021/jacs.6b06278
复制
发表时间：
2016-09-21
影响因子：
15
通讯作者：
Kahr B
中科院分区：
文献类型：
--
作者：
Cui X;Nichols SM;Arteaga O;Freudenthal J;Paula F;Shtukenberg AG;Kahr B
考虑光与非均匀、各向异性、吸收、光学活性介质的相互作用是复杂、透明材料的表征的一部分。薄组织切片中的染色生物结构具有许多这些特征，但除了使用简单的岩相显微镜外，系统的光学分析尚未建立。在这里，这个解释是由含有光吸收分子的熔体中生长出来的多晶、球状的扭曲D-甘露醇片束所致。人们早就知道，相当大比例的分子晶体很容易以具有中尺度节距的螺旋带的形式生长，但人们对这些非经典晶体形式的共性的普遍认识已经丧失。螺旋晶体的扭曲通常是通过分析岩石显微镜中的折射率调制来分析的。然而，通过在溶解的光吸收分子存在的情况下从熔体中生长扭曲晶体，可以通过分析线性和圆形二向色性来测试晶体扭曲。这里使用术语“螺旋面二向色性”来描述各向异性吸收体绕扭曲的晶丝或晶片半径行进的光学后果。D-甘露醇以两种不同的形式扭曲，α和δ。当在各种组织化学染色和纺织品染料存在的情况下从过冷的熔体中生长时，这两种多晶型在线偏振白光中是强烈的二向色性。双偶氮染料芝加哥天蓝之所以被模拟，是因为它在平行和垂直于各自球晶多晶型中的径向轴时吸收最多。使用Mueller矩阵成像偏振仪测量了光学性质，并通过考虑薄片的微观结构进行了模拟。对染色的、有图案的多晶体的光学分析澄清了从紧密堆积的纤维束中很难提取的介观结构的一些方面。
Accounting for the interactions of light with heterogeneous, anisotropic, absorbing, optically active media is part of the characterization of complex, transparent materials. Stained biological structures in thin tissue sections share many of these features, but systematic optical analyses beyond the employ of the simple petrographic microscopes have not be established. Here, this accounting is made for polycrystalline, spherulitic bundles of twisted D-mannitol lamellae grown from melts containing light-absorbing molecules. It has long been known that a significant percentage of molecular crystals readily grow as helicoidal ribbons with mesoscale pitches, but a general appreciation of the commonality of these non-classical crystal forms has been lost. Helicoidal crystal twisting was typically assayed by analyzing refractivity modulation in the petrographic microscope. However, by growing twisted crystals from melts in the presence of dissolved, light-absorbing molecules, crystal twisting can be assayed by analyzing the dichroism, both linear and circular. The term “helicoidal dichroism” is used here to describe the optical consequences of anisotropic absorbers precessing around radii of twisted crystalline fibrils or lamellae. D-Mannitol twists in two polymorphic forms, α and δ. The two polymorphs, when grown from supercooled melts in the presence of a variety of histochemical stains and textile dyes, are strongly dichroic in linearly polarized white light. The bis-azo dye Chicago sky blue is modeled because it is most absorbing when parallel and perpendicular to the radial axes in the respective spherulitic polymorphs. Optical properties were measured using Mueller matrix imaging polarimetry and simulated by taking into account the microstructure of the lamellae. The optical analysis of the dyed, patterned polycrystals clarifies aspects of the mesostructure that can be difficult to extract from bundles of tightly packed fibrils.
登录
查看更多内容
影响因子：
3.5
作者：
Ghosh, Nirmalya;Vitkin, I. Alex
通讯作者：
Vitkin, I. Alex
影响因子：
1.9
作者：
Arteaga, Oriol;Baldris, Marta;Bertran, Enric
通讯作者：
Bertran, Enric
影响因子：
15
作者：
Desgranges, Caroline;Delhommelle, Jerome
通讯作者：
Delhommelle, Jerome
影响因子：
3.6
作者：
Arteaga, Oriol;Canillas, Adolf
通讯作者：
Canillas, Adolf
影响因子：
3.8
作者：
Cohen, Dawn E.;Benedict, Jason B.;Kahr, Bart
通讯作者：
Kahr, Bart