栗钙土胡敏酸分子三维结构模型构建及其优化

本研究的目的在于确定胡敏酸的分子结构,探究其结构与性质的关系。综合应用了元素分析、红外光谱、13C核磁共振波谱等仪器分析方法对内蒙古草原样地栗钙土土壤的胡敏酸分子结构特征进行比较分析,并基于实验结构数据构建了土壤胡敏酸结构单元模型,通过模拟光谱与实际光谱比较验证了构建的二维结构有很大的可适性。借助Hyperchem软件,在MM+、AMBER、OPLS三种力场下应用分子模拟方法对三维单体结构进行分子力学、分子动力学结构优化。结果表明土壤胡敏酸的三维结构单体在AMBER力场下生成热最小,等于-1638.87 kJ/mol,所以其构象最为稳定。同时模拟其处于水环境下的分子结构,总势能及各种能量在优化前后有变化,但总体来说各种状态都较稳定。

The construction and optimization of chestnut soil humic acid' s three-dimensional molecular structure

The aim of the research is to confirm the molecular structure of humic acid and study the relationship between the structure and properties.The humic acid of chestnut soil from Inner Mongolia grassland plots was chosen as the research object and the elemental analysis,IR and 13C-NMR methods were employed to analyze the molecular structural characteristics of humic acid.The monomer molecular structure model of humic acid was proposed to match analytical results.By comparing actual spectrum with simulating spectrum,it showed that the two-dimensional structure of soil humic acid molecular model had a better suitability.This study also used Hyperchem to simulate three-dimensional monomer molecular structure models,which were optimized by molecular mechanics and molecular dynamics in the MM+,AMBER and OPLS force fields.The three-dimensional structure of soil humic acid monomers was the stablest in the AMBER force field,with the least heat of formation-1638.87 kJ/mol.The molecular structure,the total potential energy and various energies under simulation environment of water had changed after optimization,but the various states were stable generally.