@article{WernetKunnusSchrecketal.2012,
  author    = {Wernet, Philippe and Kunnus, Kristjan and Schreck, Simon and Quevedo, Wilson and Kurian, Reshmi and Techert, Simone and de Groot, Frank M. F. and Odelius, Michael and F{\"o}hlisch, Alexander},
  title     = {Dissecting local atomic and intermolecular interactions of transition-metal ions in solution with selective X-ray spectroscopy},
  series = {The journal of physical chemistry letters},
  volume    = {3},
  journal   = {The journal of physical chemistry letters},
  number    = {23},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1948-7185},
  doi       = {10.1021/jz301486u},
  pages     = {3448 -- 3453},
  year      = {2012},
  abstract  = {Determining covalent and charge-transfer contributions to bonding in solution has remained an experimental challenge. Here, the quenching of fluorescence decay channels as expressed in dips in the L-edge X-ray spectra of solvated 3d transition-metal ions and complexes was reported as a probe. With a full set of experimental and theoretical ab initio L-edge X-ray spectra of aqueous Cr3+, including resonant inelastic X-ray scattering, we address covalency and charge transfer for this prototypical transition-metal ion in solution. We dissect local atomic effects from intermolecular interactions and quantify X-ray optical effects. We find no evidence for the asserted ultrafast charge transfer to the solvent and show that the dips are readily explained by X-ray optical effects and local atomic state dependence of the fluorescence yield. Instead, we find, besides ionic interactions, a covalent contribution to the bonding in the aqueous complex of ligand-to-metal charge-transfer character.},
  language  = {en}
}
@article{KunnusJosefssonRajkovicetal.2016,
  author    = {Kunnus, Kristjan and Josefsson, I. and Rajkovic, Ivan and Schreck, Simon and Quevedo, Wilson and Beye, Martin and Weniger, C. and Gruebel, S. and Scholz, M. and Nordlund, D. and Zhang, W. and Hartsock, R. W. and Gaffney, K. J. and Schlotter, W. F. and Turner, J. J. and Kennedy, B. and Hennies, F. and de Groot, F. M. F. and Techert, S. and Odelius, Michael and Wernet, Ph. and F{\"o}hlisch, Alexander},
  title     = {Identification of the dominant photochemical pathways and mechanistic insights to the ultrafast ligand exchange of Fe(CO)(5) to Fe(CO)(4)EtOH},
  series = {Structural dynamics},
  volume    = {3},
  journal   = {Structural dynamics},
  publisher = {American Institute of Physics},
  address   = {Washington},
  issn      = {2329-7778},
  doi       = {10.1063/1.4941602},
  pages     = {16},
  year      = {2016},
  abstract  = {We utilized femtosecond time-resolved resonant inelastic X-ray scattering and ab initio theory to study the transient electronic structure and the photoinduced molecular dynamics of a model metal carbonyl photocatalyst Fe(CO)(5) in ethanol solution. We propose mechanistic explanation for the parallel ultrafast intra-molecular spin crossover and ligation of the Fe(CO)(4) which are observed following a charge transfer photoexcitation of Fe(CO)(5) as reported in our previous study [ Wernet et al., Nature 520, 78 (2015)]. We find that branching of the reaction pathway likely happens in the (1)A(1) state of Fe(CO)(4). A sub-picosecond time constant of the spin crossover from B-1(2) to B-3(2) is rationalized by the proposed B-1(2) -> (1)A(1) -> B-3(2) mechanism. Ultrafast ligation of the B-1(2) Fe(CO)(4) state is significantly faster than the spin-forbidden and diffusion limited ligation process occurring from the B-3(2) Fe(CO)(4) ground state that has been observed in the previous studies. We propose that the ultrafast ligation occurs via B-1(2) -> (1)A(1) -> (1)A'Fe(CO)(4)EtOH pathway and the time scale of the (1)A(1) Fe(CO)(4) state ligation is governed by the solute-solvent collision frequency. Our study emphasizes the importance of understanding the interaction of molecular excited states with the surrounding environment to explain the relaxation pathways of photoexcited metal carbonyls in solution. (C) 2016 Author(s).},
  language  = {en}
}