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This content will become publicly available on July 20, 2015

Title: Imaging local electric fields produced upon synchrotron X-ray exposure

Electron–hole separation following hard X-ray absorption during diffraction analysis of soft materials under cryogenic conditions produces substantial local electric fields visualizable by second harmonic generation (SHG) microscopy. Monte Carlo simulations of X-ray photoelectron trajectories suggest the formation of substantial local electric fields in the regions adjacent to those exposed to X-rays, indicating a possible electric-field–induced SHG (EFISH) mechanism for generating the observed signal. In studies of amorphous vitreous solvents, analysis of the SHG spatial profiles following X-ray microbeam exposure was consistent with an EFISH mechanism. Within protein crystals, exposure to 12-keV (1.033-Å) X-rays resulted in increased SHG in the region extending ~3 μm beyond the borders of the X-ray beam. Moderate X-ray exposures typical of those used for crystal centering by raster scanning through an X-ray beam were sufficient to produce static electric fields easily detectable by SHG. The X-ray–induced SHG activity was observed with no measurable loss for longer than 2 wk while maintained under cryogenic conditions, but disappeared if annealed to room temperature for a few seconds. In conclusion, these results provide direct experimental observables capable of validating simulations of X-ray–induced damage within soft materials. Additionally, X-ray–induced local fields may potentially impact diffraction resolution through localized piezoelectric distortionsmore » of the lattice.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States). Dept. of Chemistry
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS), General Medical Sciences and Cancer Inst. Structural Biology Facility
Publication Date:
OSTI Identifier:
1235100
Grant/Contract Number:
SC0000997; AC02-06CH11357; NIH-R01GM103401; NIH-R01GM103910
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 3; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Energy Frontier Research Centers (EFRC); Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US National Institutes of Health (NIH)
Contributing Orgs:
C3Bio partners with Purdue University (lead); Argonne National Laboratory; National Renewable Energy Laboratory; Northeastern University; University of Tennessee
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; catalysis (homogeneous); catalysis (heterogeneous); biofuels (including algae and biomass); bio-inspired; materials and chemistry by design; synthesis (self-assembly); synthesis (scalable processing); structural biology; piezoelectric; X-ray damage; synchrotron; EFISH