TY  - JOUR
A1  - Kunnus, Kristjan
A1  - Josefsson, Ida
A1  - Rajkovic, Ivan
A1  - Schreck, Simon
A1  - Quevedo, Wilson
A1  - Beye, Martin
A1  - Grübel, Sebastian
A1  - Scholz, Mirko
A1  - Nordlund, Dennis
A1  - Zhang, Wenkai
A1  - Hartsock, Robert W.
A1  - Gaffney, Kelly J.
A1  - Schlotter, William F.
A1  - Turner, Joshua J.
A1  - Kennedy, Brian
A1  - Hennies, Franz
A1  - Techert, Simone
A1  - Wernet, Philippe
A1  - Odelius, Michael
A1  - Föhlisch, Alexander
T1  - Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics
JF  - NEW JOURNAL OF PHYSICS
N2  - Ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbital and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)(5) in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given-which will be covered experimentally by upcoming transform-limited x-ray sources.
KW  - ultrafast photochemistry
KW  - excited state selectivity
KW  - anti-Stokes resonant x-ray raman scattering
KW  - free electron lasers
KW  - resonant inelastic x-ray scattering
Y1  - 2016
U6  - https://doi.org/10.1088/1367-2630/18/10/103011
SN  - 1367-2630
VL  - 18
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Kunnus, Kristjan
A1  - Zhang, Wenkai
A1  - Delcey, Mickael G.
A1  - Pinjari, Rahul V.
A1  - Miedema, Piter S.
A1  - Schreck, Simon
A1  - Quevedo, Wilson
A1  - Schröder, Henning
A1  - Föhlisch, Alexander
A1  - Gaffney, Kelly J.
A1  - Lundberg, Marcus
A1  - Odelius, Michael
A1  - Wernet, Philippe
T1  - Viewing the Valence Electronic Structure of Ferric and Ferrous Hexacyanide in Solution from the Fe and Cyanide Perspectives
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - The valence-excited states of ferric and ferrous hexacyanide ions in aqueous solution were mapped by resonant inelastic X-ray scattering (RIXS) at the Fe L-2,L-3 and N K edges. Probing of both the central Fe and the ligand N atoms enabled identification of the metal-and ligand-centered excited states, as well as ligand-to-metal and metal-to-ligand charge-transfer excited states. Ab initio calculations utilizing the RASPT2 method were used to simulate the Fe L-2,L-3-edge RIXS spectra and enabled quantification of the covalencies of both occupied and empty orbitals of pi and sigma symmetry. We found that pi back-donation in the ferric complex is smaller than that in the ferrous complex. This is evidenced by the relative amounts of Fe 3d character in the nominally 2 pi CN- molecular orbital of 7% and 9% in ferric and ferrous hexacyanide, respectively. Utilizing the direct sensitivity of Fe L-3-edge RIXS to the Fe 3d character in the occupied molecular orbitals, we also found that the donation interactions are dominated by sigma bonding. The latter was found to be stronger in the ferric complex, with an Fe 3d contribution to the nominally 5 sigma CN- molecular orbitals of 29% compared to 20% in the ferrous complex. These results are consistent with the notion that a higher charge at the central metal atom increases donation and decreases back-donation.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.jpcb.6b04751
SN  - 1520-6106
VL  - 120
SP  - 7182
EP  - 7194
PB  - American Chemical Society
CY  - Washington
ER  -