TY  - JOUR
A1  - Yang, Jie
A1  - Gühr, Markus
A1  - Vecchione, Theodore
A1  - Robinson, Matthew Scott
A1  - Li, Renkai
A1  - Hartmann, Nick
A1  - Shen, Xiaozhe
A1  - Coffee, Ryan
A1  - Corbett, Jeff
A1  - Fry, Alan
A1  - Gaffney, Kelly
A1  - Gorkhover, Tais
A1  - Hast, Carsten
A1  - Jobe, Keith
A1  - Makasyuk, Igor
A1  - Reid, Alexander
A1  - Robinson, Joseph
A1  - Vetter, Sharon
A1  - Wang, Fenglin
A1  - Weathersby, Stephen
A1  - Yoneda, Charles
A1  - Centurion, Martin
A1  - Wang, Xijie
T1  - Diffractive imaging of a rotational wavepacket in nitrogen molecules
with femtosecond megaelectronvolt electron pulses
JF  - Nature Communications
N2  - Imaging changes in molecular geometries on their natural femtosecond timescale with sub-Angstrom spatial precision is one of the critical challenges in the chemical sciences, as the nuclear geometry changes determine the molecular reactivity. For photoexcited molecules, the nuclear dynamics determine the photoenergy conversion path and efficiency. Here we report a gas-phase electron diffraction experiment using megaelectronvolt (MeV) electrons, where we captured the rotational wavepacket dynamics of nonadiabatically laser-aligned nitrogen molecules. We achieved a combination of 100 fs root-mean-squared temporal resolution and sub-Angstrom (0.76 angstrom) spatial resolution that makes it possible to resolve the position of the nuclei within the molecule. In addition, the diffraction patterns reveal the angular distribution of the molecules, which changes from prolate (aligned) to oblate (anti-aligned) in 300 fs. Our results demonstrate a significant and promising step towards making atomically resolved movies of molecular reactions.
Y1  - 2016
U6  - https://doi.org/10.1038/ncomms11232
SN  - 2041-1723
VL  - 7
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - GEN
A1  - Yang, Jie
A1  - Guehr, Markus
A1  - Vecchione, Theodore
A1  - Robinson, Matthew Scott
A1  - Li, Renkai
A1  - Hartmann, Nick
A1  - Shen, Xiaozhe
A1  - Coffee, Ryan
A1  - Corbett, Jeff
A1  - Fry, Alan
A1  - Gaffney, Kelly
A1  - Gorkhover, Tais
A1  - Hast, Carsten
A1  - Jobe, Keith
A1  - Makasyuk, Igor
A1  - Reid, Alexander
A1  - Robinson, Joseph
A1  - Vetter, Sharon
A1  - Wang, Fenglin
A1  - Weathersby, Stephen
A1  - Yoneda, Charles
A1  - Wang, Xijie
A1  - Centurion, Martin
T1  - Femtosecond gas phase electron diffraction with MeV electrons
N2  - We present results on ultrafast gas electron diffraction (UGED) experiments with femtosecond resolution using the MeV electron gun at SLAC National Accelerator Laboratory. UGED is a promising method to investigate molecular dynamics in the gas phase because electron pulses can probe the structure with a high spatial resolution. Until recently, however, it was not possible for UGED to reach the relevant timescale for the motion of the nuclei during a molecular reaction. Using MeV electron pulses has allowed us to overcome the main challenges in reaching femtosecond resolution, namely delivering short electron pulses on a gas target, overcoming the effect of velocity mismatch between pump laser pulses and the probe electron pulses, and maintaining a low timing jitter. At electron kinetic energies above 3 MeV, the velocity mismatch between laser and electron pulses becomes negligible. The relativistic electrons are also less susceptible to temporal broadening due to the Coulomb force. One of the challenges of diffraction with relativistic electrons is that the small de Broglie wavelength results in very small diffraction angles. In this paper we describe the new setup and its characterization, including capturing static diffraction patterns of molecules in the gas phase, finding time-zero with sub-picosecond accuracy and first time-resolved diffraction experiments. The new device can achieve a temporal resolution of 100 fs root-mean-square, and sub-angstrom spatial resolution. The collimation of the beam is sufficient to measure the diffraction pattern, and the transverse coherence is on the order of 2 nm. Currently, the temporal resolution is limited both by the pulse duration of the electron pulse on target and by the timing jitter, while the spatial resolution is limited by the average electron beam current and the signal-to-noise ratio of the detection system. We also discuss plans for improving both the temporal resolution and the spatial resolution.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 326 
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394989
ER  - 
TY  - JOUR
A1  - Yang, Jie
A1  - Gühr, Markus
A1  - Vecchione, Theodore
A1  - Robinson, Matthew Scott
A1  - Li, Renkai
A1  - Hartmann, Nick
A1  - Shen, Xiaozhe
A1  - Coffee, Ryan
A1  - Corbett, Jeff
A1  - Fry, Alan
A1  - Gaffney, Kelly
A1  - Gorkhover, Tais
A1  - Hast, Carsten
A1  - Jobe, Keith
A1  - Makasyuk, Igor
A1  - Reid, Alexander
A1  - Robinson, Joseph
A1  - Vetter, Sharon
A1  - Wang, Fenglin
A1  - Weathersby, Stephen
A1  - Yoneda, Charles
A1  - Wang, Xijie
A1  - Centurion, Martin
T1  - Femtosecond gas phase electron diffraction with MeV electrons
JF  - Faraday discussions
N2  - We present results on ultrafast gas electron diffraction (UGED) experiments with femtosecond resolution using the MeV electron gun at SLAC National Accelerator Laboratory. UGED is a promising method to investigate molecular dynamics in the gas phase because electron pulses can probe the structure with a high spatial resolution. Until recently, however, it was not possible for UGED to reach the relevant timescale for the motion of the nuclei during a molecular reaction. Using MeV electron pulses has allowed us to overcome the main challenges in reaching femtosecond resolution, namely delivering short electron pulses on a gas target, overcoming the effect of velocity mismatch between pump laser pulses and the probe electron pulses, and maintaining a low timing jitter. At electron kinetic energies above 3 MeV, the velocity mismatch between laser and electron pulses becomes negligible. The relativistic electrons are also less susceptible to temporal broadening due to the Coulomb force. One of the challenges of diffraction with relativistic electrons is that the small de Broglie wavelength results in very small diffraction angles. In this paper we describe the new setup and its characterization, including capturing static diffraction patterns of molecules in the gas phase, finding time-zero with sub-picosecond accuracy and first time-resolved diffraction experiments. The new device can achieve a temporal resolution of 100 fs root-mean-square, and sub-angstrom spatial resolution. The collimation of the beam is sufficient to measure the diffraction pattern, and the transverse coherence is on the order of 2 nm. Currently, the temporal resolution is limited both by the pulse duration of the electron pulse on target and by the timing jitter, while the spatial resolution is limited by the average electron beam current and the signal-to-noise ratio of the detection system. We also discuss plans for improving both the temporal resolution and the spatial resolution.
Y1  - 2016
U6  - https://doi.org/10.1039/c6fd00071a
SN  - 1359-6640
SN  - 1364-5498
VL  - 194
SP  - 563
EP  - 581
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Yang, Jie
A1  - Guehr, Markus
A1  - Shen, Xiaozhe
A1  - Li, Renkai
A1  - Vecchione, Theodore
A1  - Coffee, Ryan
A1  - Corbett, Jeff
A1  - Fry, Alan
A1  - Hartmann, Nick
A1  - Hast, Carsten
A1  - Hegazy, Kareem
A1  - Jobe, Keith
A1  - Makasyuk, Igor
A1  - Robinson, Joseph
A1  - Robinson, Matthew Scott
A1  - Vetter, Sharon
A1  - Weathersby, Stephen
A1  - Yoneda, Charles
A1  - Wang, Xijie
A1  - Centurion, Martin
T1  - Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules
JF  - Physical review letters
N2  - Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 angstrom and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet.
Y1  - 2016
U6  - https://doi.org/10.1103/PhysRevLett.117.153002
SN  - 0031-9007
SN  - 1079-7114
VL  - 117
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Tiegs, Scott D.
A1  - Costello, David M.
A1  - Isken, Mark W.
A1  - Woodward, Guy
A1  - McIntyre, Peter B.
A1  - Gessner, Mark O.
A1  - Chauvet, Eric
A1  - Griffiths, Natalie A.
A1  - Flecker, Alex S.
A1  - Acuna, Vicenc
A1  - Albarino, Ricardo
A1  - Allen, Daniel C.
A1  - Alonso, Cecilia
A1  - Andino, Patricio
A1  - Arango, Clay
A1  - Aroviita, Jukka
A1  - Barbosa, Marcus V. M.
A1  - Barmuta, Leon A.
A1  - Baxter, Colden V.
A1  - Bell, Thomas D. C.
A1  - Bellinger, Brent
A1  - Boyero, Luz
A1  - Brown, Lee E.
A1  - Bruder, Andreas
A1  - Bruesewitz, Denise A.
A1  - Burdon, Francis J.
A1  - Callisto, Marcos
A1  - Canhoto, Cristina
A1  - Capps, Krista A.
A1  - Castillo, Maria M.
A1  - Clapcott, Joanne
A1  - Colas, Fanny
A1  - Colon-Gaud, Checo
A1  - Cornut, Julien
A1  - Crespo-Perez, Veronica
A1  - Cross, Wyatt F.
A1  - Culp, Joseph M.
A1  - Danger, Michael
A1  - Dangles, Olivier
A1  - de Eyto, Elvira
A1  - Derry, Alison M.
A1  - Diaz Villanueva, Veronica
A1  - Douglas, Michael M.
A1  - Elosegi, Arturo
A1  - Encalada, Andrea C.
A1  - Entrekin, Sally
A1  - Espinosa, Rodrigo
A1  - Ethaiya, Diana
A1  - Ferreira, Veronica
A1  - Ferriol, Carmen
A1  - Flanagan, Kyla M.
A1  - Fleituch, Tadeusz
A1  - Shah, Jennifer J. Follstad
A1  - Frainer, Andre
A1  - Friberg, Nikolai
A1  - Frost, Paul C.
A1  - Garcia, Erica A.
A1  - Lago, Liliana Garcia
A1  - Garcia Soto, Pavel Ernesto
A1  - Ghate, Sudeep
A1  - Giling, Darren P.
A1  - Gilmer, Alan
A1  - Goncalves, Jose Francisco
A1  - Gonzales, Rosario Karina
A1  - Graca, Manuel A. S.
A1  - Grace, Mike
A1  - Grossart, Hans-Peter
A1  - Guerold, Francois
A1  - Gulis, Vlad
A1  - Hepp, Luiz U.
A1  - Higgins, Scott
A1  - Hishi, Takuo
A1  - Huddart, Joseph
A1  - Hudson, John
A1  - Imberger, Samantha
A1  - Iniguez-Armijos, Carlos
A1  - Iwata, Tomoya
A1  - Janetski, David J.
A1  - Jennings, Eleanor
A1  - Kirkwood, Andrea E.
A1  - Koning, Aaron A.
A1  - Kosten, Sarian
A1  - Kuehn, Kevin A.
A1  - Laudon, Hjalmar
A1  - Leavitt, Peter R.
A1  - Lemes da Silva, Aurea L.
A1  - Leroux, Shawn J.
A1  - Leroy, Carri J.
A1  - Lisi, Peter J.
A1  - MacKenzie, Richard
A1  - Marcarelli, Amy M.
A1  - Masese, Frank O.
A1  - Mckie, Brendan G.
A1  - Oliveira Medeiros, Adriana
A1  - Meissner, Kristian
A1  - Milisa, Marko
A1  - Mishra, Shailendra
A1  - Miyake, Yo
A1  - Moerke, Ashley
A1  - Mombrikotb, Shorok
A1  - Mooney, Rob
A1  - Moulton, Tim
A1  - Muotka, Timo
A1  - Negishi, Junjiro N.
A1  - Neres-Lima, Vinicius
A1  - Nieminen, Mika L.
A1  - Nimptsch, Jorge
A1  - Ondruch, Jakub
A1  - Paavola, Riku
A1  - Pardo, Isabel
A1  - Patrick, Christopher J.
A1  - Peeters, Edwin T. H. M.
A1  - Pozo, Jesus
A1  - Pringle, Catherine
A1  - Prussian, Aaron
A1  - Quenta, Estefania
A1  - Quesada, Antonio
A1  - Reid, Brian
A1  - Richardson, John S.
A1  - Rigosi, Anna
A1  - Rincon, Jose
A1  - Risnoveanu, Geta
A1  - Robinson, Christopher T.
A1  - Rodriguez-Gallego, Lorena
A1  - Royer, Todd V.
A1  - Rusak, James A.
A1  - Santamans, Anna C.
A1  - Selmeczy, Geza B.
A1  - Simiyu, Gelas
A1  - Skuja, Agnija
A1  - Smykla, Jerzy
A1  - Sridhar, Kandikere R.
A1  - Sponseller, Ryan
A1  - Stoler, Aaron
A1  - Swan, Christopher M.
A1  - Szlag, David
A1  - Teixeira-de Mello, Franco
A1  - Tonkin, Jonathan D.
A1  - Uusheimo, Sari
A1  - Veach, Allison M.
A1  - Vilbaste, Sirje
A1  - Vought, Lena B. M.
A1  - Wang, Chiao-Ping
A1  - Webster, Jackson R.
A1  - Wilson, Paul B.
A1  - Woelfl, Stefan
A1  - Xenopoulos, Marguerite A.
A1  - Yates, Adam G.
A1  - Yoshimura, Chihiro
A1  - Yule, Catherine M.
A1  - Zhang, Yixin X.
A1  - Zwart, Jacob A.
T1  - Global patterns and drivers of ecosystem functioning in rivers and riparian zones
JF  - Science Advances
N2  - River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.
Y1  - 2019
U6  - https://doi.org/10.1126/sciadv.aav0486
SN  - 2375-2548
VL  - 5
IS  - 1
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  -