摘要：

Although improved atomic scattering factors (f-curves) based on Hartree-Fock self-consistent field (SCF) with exchange calculations of atomic charge distributions have now been derived for many atoms and ions, the degree to which the Hartree-Fock scattering description may be modified by the effects of electron correlation not accounted for in such SCF calculations is so far relatively unknown, except for light atoms. There, it has been found that the significant improve- ments to Hartree-Fock values of total energy which must accompany allowance for correlation (FrSman, 1957) are generally associated with such small changes in the SCF values of charge density (see e.g. Glembot- skii et al., 1955 (B); K i b a r t a s et al., 1955 (Be); Green et al., 1959 (He); LSwdin & R6dei, 1959 (He)) t h a t the errors in Hartree-Fock f-curves of such systems which arise from neglect of correlation will be only very minor ones (Ibers, 1957). Further examination to assess whether a similar correlation insensitivity applies also to SCF charge-density data of heavier atoms is desirable however. Apart from the fact that such data are usually the best presently available over a wide range of atomic number, the adequacy of the Hartree-Fock approximation is relevant to (a), the convenience with which aspherical scattering effects (McWeeny, 1951; Freeman, 1959) may be calculated as a consequence of the total Hartree-Fock scattering power being expressible in terms of indi- vidual electron f-contributions, (b) detailed electron-

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