摘要
In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrostatic field effect on the C 1s core ionization energies of saturated molecules were evaluated,based on the topological electronegativity index TEI,the atomic electronegativity χP and the polarizability α.The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond.The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X.The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom.Further,the shielding effect ΔSi of the C 1s electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect.By introducing the ΔSi into the Slater model,a Slater-like model was obtained for calculating the C 1s core ionization energy E1,C of saturated molecules,whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C 1s core ionization energies is only 0.094eV for 81 saturated molecules.Also the cross-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99928,the average absolute error between the predicted and the experimental values is only 0.105 eV).
In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself. The charge effect, the relaxation effect and the electrostatic field effect on the C 1 s core ionization energies of saturated molecules were evaluated, based on the topological electronegativity index TEI, the atomic electronegativity XP and the polarizability α. The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond. The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X. The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom. Further,the shielding effect △Si of the C Is electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect. By introducing the △Si into the Slater model, a Slater-like model was obtained for calculating the C 1 s core ionization energy E1,c of saturated molecules, whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C ls core ionization energies is only 0. 094eV for 81 saturated molecules. Also the cress-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient re, is 0. 99928 ,the average absolute error between the predicted and the experimental values is only 0. 105 eV).
出处
《化学研究与应用》
CAS
CSCD
北大核心
2007年第7期799-805,共7页
Chemical Research and Application
基金
国家自然科学基金(20472019)资助项目
湖南省自然科学基金资助项目(06JJ4008)
湖南省教育厅重点课题资助项目(04A015)
关键词
饱和链状分子
拓扑电负性指数
原子极化度
松弛效应
屏蔽效应
内层电子电离能
saturated molecule
topological electronegativity index
atomic polarizability
relaxation effect
shielding effect
core ionization energy