氢化氧化铝的同位素效应研究

在B3LYP/6-311++G(d,p)水平上预测了Al2O3H3分子的较低能量构型.其基态构型具有C s对称性,电子态为1A′.通过研究Al2O3M3和M2(M=H,D,T)的能量E、定容热容C V和熵S,用电子振动近似讨论了Al2O3+3/2M2→Al2O3M3反应的氢同位素效应,得到了Al2O3氢化的热力学函数?H0,?S0,?G0,及平衡压力与温度的关系.研究表明,氧化物Al2O3吸附氢(氘,氚)反应的同位素排代效应顺序为氚排代氘,氘排代氢,与钛等金属的同位素排代顺序相反.但排代效应都非常弱,且随着温度的增加趋于消失.

Isotope effect of trihydride aluminum oxide

The lower energy structures of Al₂O₃H₃ molecular clusters are optimized through DFT/B3LYP connected with 6-311g++(d, p) all electrons basis set. It is found that the ground state configuration of Al₂O₃H₃ has ¹A' electronic state and C_s symmetry. Based on the research on energy, heat capacity at constant volume, entropy of Al₂O₃M₃ and M₂ (M=H, D, T), the hydrogen isotope effects of reactions between Al₂O₃ and hydrogen (deuterium or tritium) gas are studied by means of the solid electron-vibration approximation. In addition, the changes of enthalpy, entropy and Gibbs free energy, and the relation between equilibrium pressures and temperatures are presented. The investigation suggests that hydrogen can be replaced by deuterium, and deuterium can be replaced by tritium in the reactions between Al₂O₃ and M₂ with the productions of solid Al₂O₃M₃ (M=H, D, T). This replacement sequence is opposite to the metallic isotope effect e. g. for titanium, however these replacement effects are very weak, and they are weaker and weaker as the temperature increases.
Keywords： 2O₃M₃ (M=H,D,T) molecular cluster')" href="#">Al₂O₃M₃ (M=H,D,T) molecular cluster thermodynamic function isotope displacement effect change of Gibbs free energy