Periodic density functional theory study of the high-pressure behavior of crystalline L-serine-L-ascorbic acid
Periodic density functional theory study of the high-pressure behavior of crystalline L-serine-L-ascorbic acid
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结晶L-丝氨酸-L-抗坏血酸高压行为的周期密度泛函理论研究
DOI：
10.1007/s00894-015-2890-z
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发表时间：
2016-01-01
影响因子：
2.2
通讯作者：
Xiang, Ziyue
中科院分区：
文献类型：
--
作者：
Chen, Limin;Liu, Chunsheng;Xiang, Ziyue
本文通过密度泛函理论（DFT）计算对结晶L-丝氨酸-L-抗坏血酸（SAA）在0-300 GPa压力范围内的结构、电子和吸收特性进行了详细研究。我们的结果表明 SAA 的可压缩晶体是各向异性的。此外，具体分析不同压力下键长和键角的变化趋势表明，主要的结构转变发生在压力为40、50、70、100、130和150 GPa时，伴随着O2(P1)和C2(P2)以及C3(P1)和O1(P2)之间共价键的反复形成和断开，以及在100℃时新形成的五原子环。 GPa。此外，从40 GPa到230 GPa，SAA在压缩下发生复杂的氢键转变，而从240 GPa到300 GPa，SAA的晶格常数、键长和键角曲线几乎没有变化，表明230 GPa后结构稳定。然后，通过分析SAA的带隙和态密度，发现该晶体在150 GPa下经历了从绝缘体到半导体的相变，并且在压缩下变得更加敏感。此外，从吸收光谱中可以看出，随着压力的增加，SAA具有相对较高的光学活性，并且分别在50 GPa和130 GPa下观察到吸收系数的两次明显变化，表明此处发生了结构转变。
A detailed study of the structural, electronic and absorption properties of crystalline L-serine-L-ascorbic acid (SAA) in the pressure range of 0-300 GPa was performed by density-functional theory (DFT) calculations in this work. Our results show that the compressible crystal of SAA is anisotropic. Furthermore, specific analysis of the variation tendencies of bond lengths and bond angles under different pressures show that the main structural transformations occur at pressures of 40, 50, 70, 100, 130 and 150 GPa, accompanied by repeated formations and disconnections of covalent bonds between O2(P1) and C2(P2) as well as C3(P1) and O1(P2), and a newly formed five-atom ring at 100 GPa. In addition, from 40 to 230 GPa, complex hydrogen bond transformations occur in SAA under compression, while from 240 to 300 GPa, the curve of lattice constants, bond lengths and bond angles of SAA barely changes, suggesting structural stability after 230 GPa. Then, by analyzing the band gap and density of states of SAA, it was found that the crystal undergoes a phase transformation from insulator to semiconductor at 150 GPa and it becomes more sensitive under compression. In addition, a relatively high optical activity with the pressure increases of SAA was seen from the absorption spectra, and two obvious changes of absorption coefficients were also observed at 50 GPa and 130 GPa, respectively, indicating that structural transformations occur here.