TY  - JOUR
A1  - Ertan, Emelie
A1  - Savchenko, Viktoriia
A1  - Ignatova, Nina
A1  - Vaz da Cruz, Vinicius
A1  - Couto, Rafael C.
A1  - Eckert, Sebastian
A1  - Fondell, Mattis
A1  - Dantz, Marcus
A1  - Kennedy, Brian
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Föhlisch, Alexander
A1  - Odelius, Michael
A1  - Kimberg, Victor
T1  - Ultrafast dissociation features in RIXS spectra of the water molecule
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - In this combined theoretical and experimental study we report on an analysis of the resonant inelastic X-ray scattering (RIXS) spectra of gas phase water via the lowest dissociative core-excited state |1s−1O4a11〉. We focus on the spectral feature near the dissociation limit of the electronic ground state. We show that the narrow atomic-like peak consists of the overlapping contribution from the RIXS channels back to the ground state and to the first valence excited state |1b−114a11〉 of the molecule. The spectral feature has signatures of ultrafast dissociation (UFD) in the core-excited state, as we show by means of ab initio calculations and time-dependent nuclear wave packet simulations. We show that the electronically elastic RIXS channel gives substantial contribution to the atomic-like resonance due to the strong bond length dependence of the magnitude and orientation of the transition dipole moment. By studying the RIXS for an excitation energy scan over the core-excited state resonance, we can understand and single out the molecular and atomic-like contributions in the decay to the lowest valence-excited state. Our study is complemented by a theoretical discussion of RIXS in the case of isotopically substituted water (HDO and D2O) where the nuclear dynamics is significantly affected by the heavier fragments' mass.
Y1  - 2018
U6  - https://doi.org/10.1039/c8cp01807c
SN  - 1463-9076
SN  - 1463-9084
VL  - 20
IS  - 21
SP  - 14384
EP  - 14397
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Vaz da Cruz, Vinícius
A1  - Ignatova, Nina
A1  - Couto, Rafael
A1  - Fedotov, Daniil
A1  - Rehn, Dirk R.
A1  - Savchenko, Viktoriia
A1  - Norman, Patrick
A1  - Ågren, Hans
A1  - Polyutov, Sergey
A1  - Niskanen, Johannes
A1  - Eckert, Sebastian
A1  - Jay, Raphael Martin
A1  - Fondell, Mattis
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Föhlisch, Alexander
A1  - Odelius, Michael
A1  - Kimberg, Victor
A1  - Gel’mukhanov, Faris
T1  - Nuclear dynamics in resonant inelastic X-ray scattering and X-ray absorption of methanol
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - We report on a combined theoretical and experimental study of core-excitation spectra of gas and liquid phase methanol as obtained with the use of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The electronic transitions are studied with computational methods that include strict and extended second-order algebraic diagrammatic construction [ADC(2) and ADC(2)-x], restricted active space second-order perturbation theory, and time-dependent density functional theory-providing a complete assignment of the near oxygen K-edge XAS. We show that multimode nuclear dynamics is of crucial importance for explaining the available experimental XAS and RIXS spectra. The multimode nuclear motion was considered in a recently developed "mixed representation" where dissociative states and highly excited vibrational modes are accurately treated with a time-dependent wave packet technique, while the remaining active vibrational modes are described using Franck-Condon amplitudes. Particular attention is paid to the polarization dependence of RIXS and the effects of the isotopic substitution on the RIXS profile in the case of dissociative core-excited states. Our approach predicts the splitting of the 2a RIXS peak to be due to an interplay between molecular and pseudo-atomic features arising in the course of transitions between dissociative core- and valence-excited states. The dynamical nature of the splitting of the 2a peak in RIXS of liquid methanol near pre-edge core excitation is shown. The theoretical results are in good agreement with our liquid phase measurements and gas phase experimental data available from the literature. (C) 2019 Author(s).
Y1  - 2019
U6  - https://doi.org/10.1063/1.5092174
SN  - 0021-9606
SN  - 1089-7690
VL  - 150
IS  - 23
PB  - American Institute of Physics
CY  - Melville
ER  -