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采用Cz法生长了高温相偏硼酸钡α BaB2 O4 晶体 ,尺寸为50mm× 4 0mm ,晶体无色透明 ,在He Ne激光照射下无散射颗粒 ,无生长条纹。在生长过程中 ,α BaB2 O4 晶体存在强烈的晶面显露特性 ,主要与晶体所属点群R3c有密切关系 ,本文采用周期键链PBC理论分析了α BaB2 O4 晶体的结晶习性。在实验上根据晶面夹角的关系 ,结合X射线劳埃衍射照相的方法标定了晶体的显露面指数 ,两者很好地吻合。α BaB2 O4 晶体主要存在了 3组显露面即三方锥面S{ 1 10 2 }、六方柱面P{ 11 2 0 }和菱面体T{ 2 1- 34} ,且显露顺序为S >P >T ,三方锥面S与六方柱面P的晶棱方向为 [-110 1],三方锥面S与菱面体T面的晶棱方向为 [- 4 2 2 3],在晶体放肩部位处有对称分布的 6条晶棱 ,分别对应于两组晶向 [10k1i],[11k2i],i=1,2 ,3在一般情况下 ,k1i≠ 12i。
High temperature phase BaBa 4 O 4 was grown by Cz method with the size of 50mm × 40mm. The crystal was colorless and transparent. No scattering particles and no growth stripes were observed under He Ne laser irradiation. In the process of growth, α BaB2 O4 crystal has a strong crystal surface revealing characteristics, which is closely related to the point group R3c to which the crystal belongs. In this paper, the crystallization behavior of α BaB2 O4 crystal is analyzed by cyclic bond chain theory. In the experiment, the apparent index of the crystal was calibrated according to the angle between the crystal planes and the X-ray photoelectron spectroscopy. Both of them coincide well. α BaB2 O4 crystals exist mainly in three groups: S {1 10 2}, hexagonal cylinder P {11 2 0} and rhombohedral T {2 1-34}, and the order of appearance is S> P> T, the direction of the crystal edge of the three-sided conical surface S and the hexagonal cylindrical surface P is [-110 1], and the crystal edge direction of the three-sided conical surface S and the rhombohedral T surface is [-4 2 2 3] There are six symmetrical distribution of crystal edge, respectively, corresponding to the two sets of crystal orientation [10k1i], [11k2i], i = 1,2,3 In the general case, k1i ≠ 12i.