The quantum calculations on five nucleic acid bases,A,G,C,U,and T,were performed by six semiempirical methods,ab initio Hartree Fork method with twenty different basis sets,and ab initio MP2 method with three differen...The quantum calculations on five nucleic acid bases,A,G,C,U,and T,were performed by six semiempirical methods,ab initio Hartree Fork method with twenty different basis sets,and ab initio MP2 method with three different basis sets.Combining with experimental geometry parameters,two steps of principal component analysis(PCA) were processed on a large amount of data obtained from calculations.According to the results of the PCAs,some important geometric parameters of the bases were selected out to represent all of the parameters to discuss the problem related to geometric structure.展开更多
文摘The quantum calculations on five nucleic acid bases,A,G,C,U,and T,were performed by six semiempirical methods,ab initio Hartree Fork method with twenty different basis sets,and ab initio MP2 method with three different basis sets.Combining with experimental geometry parameters,two steps of principal component analysis(PCA) were processed on a large amount of data obtained from calculations.According to the results of the PCAs,some important geometric parameters of the bases were selected out to represent all of the parameters to discuss the problem related to geometric structure.