Аннотация: 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.
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Держатели документа:
KTH Royal Inst Technol, Dept Theoret Chem & Biol, S-10691 Stockholm, Sweden.
Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia.
Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.
Univ Turku, Dept Phys & Astron, FI-20014 Turun, Finland
Helmholtz Zentrum Berlin Mat & Energie, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany.
Paul Scherrer Inst, Photon Sci Div, CH-5232 Villigen, Switzerland.
Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, S-10691 Stockholm, Sweden.
Доп.точки доступа:
da Cruz, V. V.; Ignatova, N.; Игнатова Н. Ю.; Couto, R. C.; Fedotov, D. A.; Rehn, D. R.; Savchenko, V.; Савченко В.; Norman, P.; Agren, H.; Polyutov, S. P.; Полютов, Сергей Петрович; Niskanen, J.; Eckert, S.; Jay, R. M.; Fondell, M.; Schmitt, T.; Pietzsch, A.; Fohlisch, A.; Gel'mukhanov, F.; Гельмуханов, Фарис Хафизович; Odelius, M.; Kimberg, V.; Кимберг, Виктор Валерьевич; Swedish Research Council [VR 2015-04510, 2015-03781, 2015-03956, 2016-03619]; Knut and Alice Wallenberg Foundation [KAW-2013.0020]; Carl Tryggers Foundation; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [CNPq 234625/2014-7]; European Research Council under the European Union [669531 EDAX]; Helmholtz Virtual Institute "Dynamic Pathways in Multidimensional Landscapes" [VI419]; Swedish National Infrastructure for Computing [SNIC 2018/3-104, 023/07-18]; Ministry of Education and Science of the Russian Federation [3.2662.2017]