TY  - JOUR
AU  - Young, Linda
AU  - Ueda, Kiyoshi
AU  - Gühr, Markus
AU  - Bucksbaum, Philip H
AU  - Simon, Marc
AU  - Mukamel, Shaul
AU  - Rohringer, Nina
AU  - Prince, Kevin C
AU  - Masciovecchio, Claudio
AU  - Meyer, Michael
AU  - Rudenko, Artem
AU  - Rolles, Daniel
AU  - Bostedt, Christoph
AU  - Fuchs, Matthias
AU  - Reis, David A
AU  - Santra, Robin
AU  - Kapteyn, Henry
AU  - Murnane, Margaret
AU  - Ibrahim, Heide
AU  - Légaré, François
AU  - Vrakking, Marc
AU  - Isinger, Marcus
AU  - Kroon, David
AU  - Gisselbrecht, Mathieu
AU  - L’Huillier, Anne
AU  - Wörner, Hans Jakob
AU  - Leone, Stephen R
TI  - Roadmap of ultrafast x-ray atomic and molecular physics
JO  - Journal of physics / B
VL  - 51
IS  - 3
SN  - 0022-3700
CY  - Bristol
PB  - IOP Publ.
M1  - PUBDB-2019-00875
SP  - 032003 
PY  - 2018
AB  - X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (1020 W cm−2) of x-rays at wavelengths down to  1 Ångstrom, and HHG provides unprecedented time resolution ( 50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scales can be referenced to the chemically significant carbon K-edge at a photon energy of  280 eV (44 Ångstroms) and the bond length in methane of  1 Ångstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Ångstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Ångstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities since its discovery roughly 30 years ago, showcasing experiments in AMO physics and other applications. Here we capture the perspectives of 17 leading groups and organize the contributions into four categories: ultrafast molecular dynamics, multidimensional x-ray spectroscopies; high-intensity x-ray phenomena; attosecond x-ray science. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000419798100001
DO  - DOI:10.1088/1361-6455/aa9735
UR  - https://bib-pubdb1.desy.de/record/419011
ER  -