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【答案】应助回帖
★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★
感谢参与，应助指数 +1
lsyang: 金币+15, ★★★★★最佳答案, 谢谢 2013-03-06 16:08:47
可以仔细看看下面一段，对号入座即可。
SFAC label a1 b1 a2 b2 a3 b3 a4 b4 c f' f" mu r wt
Scattering factor in the form of an exponential series, followed by real and imaginary dispersion terms, linear absorption coefficient, covalent radius and atomic weight. Except for the 'label' and atomic weight the format is the same as that used in SHELX-76. label consists of up to 4 characters beginning with a letter (e.g. Ca2+) and should be included before a1; for consistency the first label character may be a '$', but this is ignored (note however that the '$', if used, counts as one of the four characters, leaving only three for the rest of the label). The two SFAC formats may be used in the same .ins file; the order of the SFAC instructions (and the order of element names in the first type of SFAC instruction) define the scattering factor numbers which are referenced by atom instructions. The units of mu should be barns/atom, as in Table 4.2.4.2 of International Tables, Volume C (see above). For neutrons this format should be used, with a1...b4 set to zero. |
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