2X (M=Li, na; X=H, F): Ab-initio study of basis set effect and electron correlation]]>

摘要

Graphical abstract Display Omitted Highlights ? Diffuse electron systems. ? Vertical ionization energy. ? Basis set effect. ? Electron correlation (MP2, CC). Abstract Present investigation reveals that diffuse electron compounds M2X predict large (106 a.u.) γav value. The basis set dependence of γav showed that the quality of basis function rather than its size is more important. Sadlej’s Pol basis set which is nearly four times less in size than aug-cc-pVQZ can give reliable estimate of γav. MP2 method in conjunction with large basis sets can give comparable results of γav that could be obtained from CCSD or CCSD(T). Higher order energy correction to MP2 leads to oscillatory behavior but inclusion of triple excitations to CCSD improves the magnitude of γav. ]]>