In this paper, we review the main problem concerning the calculation of X-ray
scattering of simulated model systems, namely their finite size. A novel method
based on the Rayleigh-Debye-Gans approximation was derived, which allows
sidestepping this issue by complementing the missing surroundings of each
particle with an average image of the system. The method was designed to
operate directly on particle configurations without an intermediate step (e.g.,
calculation of pair distribution functions): in this way, all information
contained in the configurations was preserved. A comparison of the results
against those of other known methods showed that the new method combined
several favourable properties: an arbitrary q-scale, scattering curves free of
truncation artifacts and good behaviour down to the theoretical lower limit of
the q-scale. A test of computational efficiency was also performed to establish
a relative scale between the speeds of all known methods: the reciprocal
lattice approach, the brute force method, the Fourier transform approach and
the newly presented complemented system approach.Comment: 6 pages, 5 figures. Copyright 2010 American Institute of Physics.
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following article appeared in The Journal of Chemical Physics and may be
found at http://link.aip.org/link/?jcp/133/17412