Determining Molecular Structures and Conformations Directly from Electron Diffraction using a Genetic Algorithm
- Creators
- Habershon, Scott
- Zewail, Ahmed H.
Abstract
A global optimization strategy, based upon application of a genetic algorithm (GA), is demonstrated as an approach for determining the structures of molecules possessing significant conformational flexibility directly from gas-phase electron diffraction data. In contrast to the common approach to molecular structure determination, based on trial-and-error assessment of structures available from quantum chemical calculations, the GA approach described here does not require expensive quantum mechanical calculations or manual searching of the potential energy surface of the sample molecule, relying instead upon simple comparison between the experimental and calculated diffraction pattern derived from a proposed trial molecular structure. Structures as complex as all-trans retinal and p-coumaric acid, both important chromophores in photosensing processes, may be determined by this approach. In the examples presented here, we find that the GA approach can determine the correct conformation of a flexible molecule described by 11 independent torsion angles. We also demonstrate applications to samples comprising a mixture of two distinct molecular conformations. With these results we conclude that applications of this approach are very promising in elucidating the structures of large molecules directly from electron diffraction data.
Additional Information
© 2006 WILEY-VCH Verlag GmbH & Co. Received: September 27, 2005. Published online on January 13, 2006. This work was supported by a grant from the National Science Foundation and the Air Force Office of Scientific Research. We would like to acknowledge Jonathan Feenstra and Dmitry Shorokhov for helpful discussions, and Sang Tae Park for careful reading of and comments on the manuscript.Additional details
- Eprint ID
- 69678
- DOI
- 10.1002/cphc.200500532
- Resolver ID
- CaltechAUTHORS:20160816-145535775
- NSF
- Air Force Office of Scientific Research (AFOSR)
- Created
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2016-08-17Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field