摘要
构建水滑石(Mg3Al-LDHs-Cl-nH2O)周期性计算模型,采用密度泛函理论-赝势平面波法的CASTEP/LDA(局域密度近似)程序,在CA-PZ水平上对模型进行几何全优化和弹性常数计算.从弹性常数Cij、切变模量、杨氏模量和泊松比等方面研究了层间水分子含量(n)对材料力学性质的影响.计算结果表明,层间水分子含量对材料的力学性质有很大的影响.层间水分子能提高体系总体的抗压性能,当n=1时,材料的抗压性能最好;当n=2时,材料的抵抗剪切变形的能力最差,体系最柔软.层间水分子对材料杨氏模量的影响较大,对泊松比的影响并不明显.且层间水分子对材料横向的力学性能起到平均化作用,最终使材料在x轴和y轴方向上的抗压性能和膨胀率趋于一致.
A periodical model for Mg3Al-LDHs-Cl-nH2O has been proposed.A geometry optimization and elastic constant calculation for the layered double hydroxides（LDHs） were carried out using the CASTEP/LDA（local density approximation） procedure at the CA-PZ level.The influence of interlayer water content（n） on the mechanical properties of the materials was investigated by analyzing the elastic constants Cij,shear modulus,Young＇s modulus,and Poisson＇s ratio,etc.Results indicated that the interlayer water content greatly impacted the mechanical properties of the materials.Interlayer water can enhance the compression properties of the overall system.When n=1,the compression properties of the material was best.When n=2,the capacity of the material to resist shear deformation was the worst and the system was most flexible.Interlayer water molecules greatly impacted the Young＇s modulus of the material while the impact on Poisson＇ s ratio was not obvious.Interlayer water molecules played a horizontal role of averaging the mechanical properties of the materials.The compression performance and the expansion of the material in the x-axis and y-axis tended to be the same.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2009年第11期2325-2328,共4页
Acta Physico-Chimica Sinica
基金
浙江省自然科学基金(Y406069)资助项目~~
关键词
密度泛函理论
水滑石
弹性常数
层间水含量
Density functional theory
Elastic constant
Interlayer water molecule content
Layered double hydroxide
