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Kwon, Oh Hoon
Ultrafast Laser Spectroscopy and Nano-microscopy (ULSaN Lab)
Research Interests
  • Femtochemistry/biology, 4D electron microscopy, structural dynamics, materials phenomena

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4D visualization of embryonic, structural crystallization by single-pulse microscopy

Cited 25 times inthomson ciCited 21 times inthomson ci
Title
4D visualization of embryonic, structural crystallization by single-pulse microscopy
Author
Kwon, Oh HoonBarwick, BrettPark, Hyun SoonBaskin, J. SpencerZewail, Ahmed H.
Issue Date
2008-06
Publisher
NATL ACAD SCIENCES
Citation
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, v.105, no.25, pp.8519 - 8524
Abstract
In many physical and biological systems the transition from an amorphous to ordered native structure involves complex energy landscapes, and understanding such transformations requires not only their thermodynamics but also the structural dynamics during the process. Here, we extend our 4D visualization method with electron imaging to include the study of irreversible processes with a single pulse in the same ultrafast electron microscope (UEM) as used before in the single-electron mode for the study of reversible processes. With this augmentation, we report on the transformation of amorphous to crystalline structure with silicon as an example. A single heating pulse was used to initiate crystallization from the amorphous phase while a single packet of electrons imaged selectively in space the transformation as the structure continuously changes with time. From the evolution of crystallinity in real time and the changes in morphology, for nanosecond and femtosecond pulse heating, we describe two types of processes, one that occurs at early time and involves a nondiffusive motion and another that takes place on a longer time scale. Similar mechanisms of two distinct time scales may perhaps be important in biomolecular folding.
URI
https://scholarworks.unist.ac.kr/handle/201301/8747
URL
http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=47249092744
DOI
10.1073/pnas.0803344105
ISSN
0027-8424
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CHM_Journal Papers
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