Publication Date:
2009-07-11
Description:
Chemical bonding dynamics are fundamental to the understanding of properties and behavior of materials and molecules. Here, we demonstrate the potential of time-resolved, femtosecond electron energy loss spectroscopy (EELS) for mapping electronic structural changes in the course of nuclear motions. For graphite, it is found that changes of milli-electron volts in the energy range of up to 50 electron volts reveal the compression and expansion of layers on the subpicometer scale (for surface and bulk atoms). These nonequilibrium structural features are correlated with the direction of change from sp2 [two-dimensional (2D) graphene] to sp3 (3D-diamond) electronic hybridization, and the results are compared with theoretical charge-density calculations. The reported femtosecond time resolution of four-dimensional (4D) electron microscopy represents an advance of 10 orders of magnitude over that of conventional EELS methods.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carbone, Fabrizio -- Kwon, Oh-Hoon -- Zewail, Ahmed H -- New York, N.Y. -- Science. 2009 Jul 10;325(5937):181-4. doi: 10.1126/science.1175005.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19589997" target="_blank"〉PubMed〈/a〉
Keywords:
Crystallization
;
Graphite/*chemistry
;
Lasers
;
*Microscopy, Energy-Filtering Transmission Electron
;
*Physicochemical Processes
;
*Spectroscopy, Electron Energy-Loss
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
