期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：13
页码：5499-5502
DOI：10.1073/pnas.88.13.5499
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Three-dimensional electron diffraction intensity data from poly(epsilon-caprolactone) are used for an ab initio phase determination based on the probabilistic estimate of three- and four-phase structure invariants in space group P212121. From the initial phase set of 30 reflections (two of which are incorrect) of the 47 in the total data set, computed electrostatic potential maps produce a recognizable structure that can be refined by Fourier techniques and atomic displacement. The final structure (R = 0.21), which is very similar to one found in an earlier fiber x-ray study, shows that the polymer chain must adopt a nonplanar conformation around the ester linkage.
