摘要
运用包括非迭代三激发电子相关耦合簇CCSD(T)方法和Dunning等人使用的相关一致aug-CC-PVxZ(x=D,T,Q,5)自洽基组对XF(X=H,D,T)分子进行了结构优化,优化值然后被插值到CBS极限.结果表明随着x的增大aug-CC-PVxZ系列基组优化的结构逼近实验值,计算频率与实验值最大差距不足1%,最小仅为0.099%,平衡间距最大只有0.8%的差距.通过计算还表明:在结构优化和频率分析时CCSD(T)显示出优秀的特性,但在研究与边界态或解离有关的问题时,CCSD(T)不能给出良好的结果,相反CCSD方法却能给出合理的解离极限.最后我们研究了XF(X=H,D,T)的分子势能函数和光谱常数,理论结果与已知实验值吻合的非常好.首次获得了XF(X=H,D,T)系列分子的ωeye,ωeze,β,γ,He,Fe值.
The equilibrium structure and vibrational frequency of FX（X=H,D,T） molecules are calculated at the CCSD（T） level in conjunction with serials of basis sets aug-CC-PVxZ（x=D,T,Q,5）,and then the optimized values are extrapolated to CBS limitation.The theoretical results are shown to be in greater agreement with the experiments as x increases.The difference is only 1% between experiments and the present calculation in vibrational frequency and the maximum equilibrium nuclear distance is 0.8%.Calculations indicate that CCSD（T） is the best method in the optimization and frequency analysis but it cannot give a correct limitation in the study of dissociation process whereas CCSD can solve this question and give a reasonable dissociation limitation.The analytic potential energy function of FX（X=H,D,T） is derived by least square fitting to Murrell-Sorbie and Dunham function,and the force constants and molecular constants are obtained.The results in this study are in good agreement with the experiment data.The ωeye,ωeze,β,γ,He,Fe values are obtained for the first time.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2010年第1期54-58,共5页
Journal of Southwest University(Natural Science Edition)
基金
国家自然科学基金青年基金资助项目(20804060/B0405)
