Time-Resolved Electron Diffraction from Selectively Aligned Molecules

Reckenthaeler, Peter; Centurion, Martin; Fuß, Werner; Trushin, Sergei A.; Krausz, Ferenc; Fill, Ernst E.

doi:10.1103/physrevlett.102.213001

Cited by 115 publications

(100 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, it enables delivering electron bunches with orders-of-magnitude higher charge while maintaining micron-scale probe size and femtosecond-scale pulse duration. In addition, the relativistic nature of MeV electron probe naturally solves the problem of velocity mismatch in which a sub-relativistic electron probe lags an optical pump pulse, which is critical to achieve sub-100 fs temporal resolution for gas phase samples [18][19][20] . Electrons with higher energies also provide a larger penetration depth to enable access to thicker specimens.…”

mentioning

confidence: 99%

Femtosecond mega-electron-volt electron microdiffraction

Shen

Lundström

et al. 2018

Ultramicroscopy

View full text Add to dashboard Cite

Instruments to visualize transient structural changes of inhomogeneous materials on the nanometer scale with atomic spatial and temporal resolution are demanded to advance materials science, bioscience, and fusion sciences. One such technique is femtosecond electron microdiffraction, in which a short pulse of electrons with femtosecondscale duration is focused into a micron-scale spot and used to obtain diffraction images to resolve ultrafast structural dynamics over localized crystalline domain. In this letter, we report the experimental demonstration of time-resolved mega-electron-volt electron microdiffraction which achieves a 5 μm root-mean-square (rms) beam size on the sample and a 100 fs rms temporal resolution. Using pulses of 10k electrons at 4.2 MeV energy with a normalized emittance 3 nm-rad, we obtained high quality diffraction from a single 10 μm paraffin ( ) crystal. The phonon softening mode in optical-pumped polycrystalline Bi was also time-resolved, demonstrating the temporal resolution limits of our instrument design. This new characterization capability will open many research opportunities in material and biological sciences.Time-resolved x-ray 1-3 and electron microbeams 4-6 are emerging tools with broad applications in science and technology. Achieving high temporal resolving power provides insight into structural dynamics of materials in non-equilibrium states for understanding and controlling of energy and matter 7 . Delivering a focused, micron-scale beam to a sample under study is of paramount importance, as it enables the study of samples that cannot be prepared at the macroscale, or are intrinsically inhomogeneous. For example, the lateral size of a "large" protein crystal is typically less than 100 μm. Further, small protein crystals almost always exhibit greater perfection and less impurity than large crystals 8 . Matching the beam size to that of the small protein crystal sample provides the best signal-to-noise (SNR) ratio for crystallography. The inhomogeneous nature of natural and nanoscale materials also requires micron-scale probes to determine local composition, chemistry, and crystalline structure. With the advent of high brightness x-ray free-electron lasers and efficient x-ray focusing optics, x-ray microbeams with femtosecond level temporal resolving power have been achieved [9][10][11][12] . Extensive research and development efforts are underway to push the frontier of electron microbeams towards the femtosecond time scales temporal resolution in the Ultrafast Electron Diffraction (UED).Electron microdiffraction with continuous wave beams is a well-established technique in conventional transmission electron microscopy (TEM) 13 . Recently, ultrafast electron microscopy has been built by modifying a conventional TEM from thermionic or field emission electron sources to ultrafast laser-excited photoemission electron sources [14][15] , allowing timeresolved optical pump -electron probe experiments. Dedicated kilo-electron-volt (keV) ultrafast electron diffraction machines ha...

show abstract

mentioning

confidence: 99%

Femtosecond mega-electron-volt electron microdiffraction

Shen

Lundström

et al. 2018

Ultramicroscopy

View full text Add to dashboard Cite

show abstract

“…Larger molecules, possessing several interatomic distances, would require high degrees of alignment, in addition to mid-infrared FABLES pulses. In general, 3D alignment is necessary to reconstruct the stereo-structure of a molecule without a priori knowledge since the information obtained from randomly oriented molecules is restricted to the radial function 1,3,48 , that is, internuclear distances. Thus, by combining by the rotational revival time.…”

Section: Discussionmentioning

confidence: 99%

Diffraction using laser-driven broadband electron wave packets

Blaga

Zhang

et al. 2014

Nat Commun

View full text Add to dashboard Cite

Directly monitoring atomic motion during a molecular transformation with atomic-scale spatio-temporal resolution is a frontier of ultrafast optical science and physical chemistry. Here we provide the foundation for a new imaging method, fixed-angle broadband laser-induced electron scattering, based on structural retrieval by direct one-dimensional Fourier transform of a photoelectron energy distribution observed along the polarization direction of an intense ultrafast light pulse. The approach exploits the scattering of a broadband wave packet created by strong-field tunnel ionization to self-interrogate the molecular structure with picometre spatial resolution and bond specificity. With its inherent femtosecond resolution, combining our technique with molecular alignment can, in principle, provide the basis for time-resolved tomography for multi-dimensional transient structural determination.

show abstract

“…This significantly aids in 1D and 3D alignment and orientation experiments 17,26,27,49 . This is a crucial prerequisite for the next generation of molecular physics experiments extracting molecular frame information from complex molecules, such as molecular orbital imaging 2 or diffraction 50 experiments.…”

Section: Discussionmentioning

confidence: 99%

Spatial Separation of Molecular Conformers and Clusters

Horke

Trippel

Chang

et al. 2014

JoVE

View full text Add to dashboard Cite

Gas-phase molecular physics and physical chemistry experiments commonly use supersonic expansions through pulsed valves for the production of cold molecular beams. However, these beams often contain multiple conformers and clusters, even at low rotational temperatures. We present an experimental methodology that allows the spatial separation of these constituent parts of a molecular beam expansion. Using an electric deflector the beam is separated by its mass-to-dipole moment ratio, analogous to a bender or an electric sector mass spectrometer spatially dispersing charged molecules on the basis of their mass-to-charge ratio. This deflector exploits the Stark effect in an inhomogeneous electric field and allows the separation of individual species of polar neutral molecules and clusters. It furthermore allows the selection of the coldest part of a molecular beam, as low-energy rotational quantum states generally experience the largest deflection. Different structural isomers (conformers) of a species can be separated due to the different arrangement of functional groups, which leads to distinct dipole moments. These are exploited by the electrostatic deflector for the production of a conformationally pure sample from a molecular beam. Similarly, specific cluster stoichiometries can be selected, as the mass and dipole moment of a given cluster depends on the degree of solvation around the parent molecule. This allows experiments on specific cluster sizes and structures, enabling the systematic study of solvation of neutral molecules. Video LinkThe video component of this article can be found at

show abstract

Time-Resolved Electron Diffraction from Selectively Aligned Molecules

Cited by 115 publications

References 27 publications

Femtosecond mega-electron-volt electron microdiffraction

Femtosecond mega-electron-volt electron microdiffraction

Diffraction using laser-driven broadband electron wave packets

Spatial Separation of Molecular Conformers and Clusters

Contact Info

Product

Resources

About