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Evaluating the electron density model by applying an imaginary modification

Published online by Cambridge University Press:  18 December 2017

Hui Li*
Affiliation:
Beijing University of Technology, Beijing 100124, China
Meng He*
Affiliation:
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Ze Zhang
Affiliation:
Zhejiang University, Hangzhou 310014, China
*
a)Author to whom correspondence should be addressed. Electronic mail: huilicn@yahoo.com, mhe@nanoctr.cn
a)Author to whom correspondence should be addressed. Electronic mail: huilicn@yahoo.com, mhe@nanoctr.cn

Abstract

A function has been proposed to evaluate the electron density model constructed by inverse Fourier transform using the observed structure amplitudes and trial phase set. The strategy of this function is applying an imaginary electron density modification to the model, and then measuring how well the calculated structure amplitudes of the modified model matches the expected structure amplitudes for the modified correct model. Since the correct model is not available in advance, a method has been developed to estimate the structure amplitudes of the modified correct model. With the estimated structure amplitudes of the modified correct model, the evaluation function can be calculated approximately. Limited tests on simulated diffraction data indicate that this evaluation function may be valid at the data resolution better than 2.5 Å.

Type
Technical Articles
Copyright
Copyright © International Centre for Diffraction Data 2017 

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