摘要
用多体微扰方法MP6对三个非氢原子组成的分子体系 ,分别在cc pVDZ、cc pVTZ、和cc pVQZ基组下 ,进行了构型优化计算 ,并利用Dunning提出的经验公式把结果外推到CBS极限。由于各种误差的相互抵消 ,MP2的构型优化结果较MP6或MP4的好。用耦合簇方法 (CCSD(T) )在同样条件下进行了优化计算 ,结果比微扰方法更具有优势。
MP6 geometry optimizations with cc-pVDZ,cc-pVTZ,and cc-pVQZ basis ests were carried out for the systems with three atoms,e.g.CO_2 and O_3,then CBS limits were obtained by using Dunning,sextrapolation equation.Because of error cancellation,MP2 can provide better quality geometry than MP6 or MP4.For comparison,coupled cluster methods (CCSD(T))were applied to the same geometry optimization cases,and the results show that CC methods have more advantages than MP methods in geometry optimizations.
出处
《化学研究与应用》
CAS
CSCD
北大核心
2004年第3期343-345,共3页
Chemical Research and Application
基金
国家自然科学基金资助课题 2 0 173 0 3 7
关键词
分子构型
优化
多体微扰理论
CBS极限
耦合簇方法
geometry optimization
moller-plesset perturbation theory
coupled cluster theory
CSB limit
