TY - JOUR A1 - Liu, Ji-Cai A1 - Vaz da Cruz, Vinicius A1 - Polyutov, Sergey A1 - Föhlisch, Alexander T1 - Recoil-induced dissociation in hard-x-ray photoionization JF - Physical review : A, Atomic, molecular, and optical physics N2 - We predict the recoil-induced molecular dissociation in hard-x-ray photoionization. The recoil effect is caused by electronic and photon momentum exchange with the molecule. We show the strong role of relativistic effects for the studied molecular fragmentation. The recoil-induced fragmentation of the molecule is caused by elongation of the bond due to the vibrational recoil effect and because of the centrifugal force caused by the rotational recoil. The calculations of the x-ray photoelectron spectra of the H-2 and NO molecules show that the predicted effects can be observed in high-energy synchrotrons like SOLEIL, SPring-8, PETRA, and XFEL SACLA. The relativistic effect enhances the recoil momentum transfer and makes it strongly sensitive to the direction of ejection of the fast photoelectron with respect to the photon momentum. Y1 - 2019 U6 - https://doi.org/10.1103/PhysRevA.100.053408 SN - 2469-9926 SN - 2469-9934 VL - 100 IS - 5 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Eckert, Sebastian A1 - Vaz da Cruz, Vinicius A1 - Ertan, Emelie A1 - Ignatova, Nina A1 - Polyutov, Sergey A1 - Couto, Rafael C. A1 - Fondell, Mattis A1 - Dantz, Marcus A1 - Kennedy, Brian A1 - Schmitt, Thorsten A1 - Pietzsch, Annette A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - One-dimensional cuts through multidimensional potential-energy surfaces by tunable x rays JF - Physical review : A, Atomic, molecular, and optical physics N2 - The concept of the potential-energy surface (PES) and directional reaction coordinates is the backbone of our description of chemical reaction mechanisms. Although the eigenenergies of the nuclear Hamiltonian uniquely link a PES to its spectrum, this information is in general experimentally inaccessible in large polyatomic systems. This is due to (near) degenerate rovibrational levels across the parameter space of all degrees of freedom, which effectively forms a pseudospectrum given by the centers of gravity of groups of close-lying vibrational levels. We show here that resonant inelastic x-ray scattering (RIXS) constitutes an ideal probe for revealing one-dimensional cuts through the ground-state PES of molecular systems, even far away from the equilibrium geometry, where the independent-mode picture is broken. We strictly link the center of gravity of close-lying vibrational peaks in RIXS to a pseudospectrum which is shown to coincide with the eigenvalues of an effective one-dimensional Hamiltonian along the propagation coordinate of the core-excited wave packet. This concept, combined with directional and site selectivity of the core-excited states, allows us to experimentally extract cuts through the ground-state PES along three complementary directions for the showcase H2O molecule. Y1 - 2018 U6 - https://doi.org/10.1103/PhysRevA.97.053410 SN - 2469-9926 SN - 2469-9934 VL - 97 IS - 5 PB - American Physical Society CY - College Park 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 -