标题： 血红素的填充效率和光学性质 显示英文标题

标题： Space-filling efficiency and optical properties of hemoglycin

摘要： 空的、广泛的低密度晶格结构的血甘氨酸被研究，以了解在空间中，可能早在宇宙时间8亿年时，一种由甘氨酸和铁组成的棒状聚合物是如何占据主导地位的。 要回答的一个核心问题是，具有钻石2H对称性的血甘氨酸棒状晶格是否代表了通过相同棒状结构的规则排列对空间最有效的覆盖。 从每个血甘氨酸晶格顶点的四面体对称性出发，我们发现阿基米德的正截角四面体可以被扩展，直到相邻的六边形面重合，此时空间填充率为23/24或95.8333%。 我们描述了具有钻石2H棒状晶格的单位细胞及其符合的几乎完全填充空间的结构，该结构具有相同的对称性。 通过最少的分子材料实现最大的空间填充，可以使血甘氨酸在分子云中促进聚集，有助于尘埃的组成，并为其在陨石样品和降落到地球的彗星物质中的广泛存在提供背景。 血甘氨酸晶格实体的光学性质来源于对紫外和可见光跃迁能量和强度的量子计算。 血甘氨酸的消光曲线复制了已知的218nm紫外吸收特征，即紫外突起，同时还包括在天文学消光数据通用汇编中存在的两个可见吸收特征。 显示英文摘要

摘要： The empty, extensive low-density lattice topology of hemoglycin is examined to understand how in space, and possibly as early as 800M years into cosmic time a rod-like polymer of glycine and iron came into dominance. A central question to be answered is whether the hemoglycin rod lattice with diamond 2H symmetry represents the most efficient covering of space by a regular arrangement of identical rods. Starting from the tetrahedral symmetry of every hemoglycin lattice vertex we find that the regular truncated tetrahedron of Archimedes may be expanded until neighboring hexagon faces are coincident, at which point space filling is 23/24 or 95.8333% complete. We describe the unit cells of the diamond 2H rod lattice and its conforming near-complete space-filling structure, which has identical symmetry. Maximum space filling via a minimum of molecular material can allow hemoglycin to drive accretion in molecular clouds, contributing to the composition of dust, and providing a background for its widespread presence in meteoritic samples and in cometary material that falls to Earth. The optical properties of hemoglycin lattice entities are derived from quantum calculations of ultraviolet and visible transition energies and strengths. The hemoglycin extinction curve duplicates the nominal 218nm ultraviolet absorption feature known as the UV bump, together with two visible absorption features present in a generic compilation of astronomical extinction data.