The crystal structure of trimethylarsine oxide dihydrate, (CH3)3AsO⋅2H2O, (TMAO dihydrate) has been solved using parallel tempering with the FOX software package and refined using synchrotron powder diffraction data obtained from beamline 08B1-1 at the Canadian Light Source. Rietveld refinement, performed with the software package GSASII, yielded orthorhombic lattice parameters of a = 13.3937(4) Å, b = 9.53025(30) Å, and c = 11.5951(3) Å (Z = 8, space group Pbca). The Rietveld refined structure was compared with density functional theory calculations performed with VASP and shows reasonable agreement. Arsenic K-edge X-ray absorption spectroscopy analysis also revealed additional information on the electronic structure of the arsenic atom within the TMAO dihydrate structure.

中文翻译：

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三甲基氧化胂二水合物(CH3)3AsO·2H2O的晶体结构和X射线吸收光谱

三甲基氧化胂二水合物的晶体结构，（CH3)3AsO·2H2O, (TMAO 二水合物) 已通过 FOX 软件包的平行回火解决，并使用从加拿大光源处的光束线 08B1-1 获得的同步加速器粉末衍射数据进行了改进。使用软件包 GSASII 进行 Rietveld 细化，得到斜方晶格参数一种= 13.3937(4) 埃，b= 9.53025(30) Å，和C= 11.5951(3) Å (Z= 8，空间群铅酸铅）。Rietveld 细化结构与用 VASP 进行的密度泛函理论计算进行了比较，并显示出合理的一致性。砷 K 边 X 射线吸收光谱分析还揭示了有关 TMAO 二水合物结构中砷原子电子结构的更多信息。