锂辉石表面环烷酸吸附行为的量子化学

摘要

采用量子化学计算、红外光谱分析研究了环烷酸在锂辉石表面的吸附行为.通过计算表面能选取锂辉石(110)面为最佳解理面,并构建了无虚频的稳定环烷酸分子模型,运用分子动力学模拟得到环烷酸与锂辉石(110)面的最佳吸附构型.对最优吸附构型进行了量子化学计算,研究了其结构、电荷分布、差分电荷密度以及态密度等.结果表明:锂辉石(110)面吸附环烷酸分子后表面原子都向锂辉石内部弛豫,环烷酸吸附后的构型发生明显的变化,其羰基氧原子负电性得到增强,非羰基原子的负电性得到削弱,环烷酸与锂辉石的作用是通过羰基氧原子实现的.环烷酸与锂辉石吸附后,锂辉石(110)面的电子云重新分配,氧原子的电荷云密度增强并向周围区域发散开来,环烷酸整体态密度峰左移且费米能级附近的态密度峰由价带变为导带,体系趋向于稳定存在.红外光谱分析进一步表明:环烷酸在锂辉石表面吸附是物理吸附作用.%The mechanism of flotation of naphthenic acid on spodumene was studied by using the method of quantum chemistry calculation and infrared spectrum analysis.The paper has selected the (110) surface as the best cleavage plane by calculating different surfaces' energy and has built stability naphthenic acid model with no imaginary frequency,then has got the best configuration for adsorption of naphthenic acid on spodumene (110) surface by using the method of molecular dynamics simulation.The structure,charge distribution,differential charge density and state density to the best adsorption configuration were studied.The results show that the atoms on the (110) surface relaxes to the spodumene inside when the naphthenic acid molecule is adsorbed on the (110) surface.At the same time,the configuration of the naphthenic acid changes obviously.The electronegative of the carbonyl oxygen atoms is stronger and those of the other oxygen atoms are weakened to the adsorbed naphthenic acid molecule.The interaction between naphthenic acid and spodumene is achieved by carbonyl atoms.After adsorption,the electron cloud is redistributed and the charge cloud density of the oxygen atoms increase and spread to the surrounding area on the spodumene (110) surface.The state density peak of the naphthenic acid molecule shifts to the left but the peak near the Fermi lever has changed from valence band to the conduction band.The adsorption structure tends to be stable.The infrared spectral analysis further shows that the naphthenic acid is physical adsorption on the spodumene surface.