%0 Journal Article
%A Uemura, Yohei
%A Yamamoto, Kohei
%A Niwa, Yasuhiro
%A Buttiens, Thomas
%A Elnaggar, Hebatalla
%A Wang, Ru-pan
%A Lazemi, Masoud
%A de Groot, Frank
%A Katayama, Tetsuo
%A Yabashi, Makina
%A Milne, Christopher J.
%A Yokoyama, Toshihiko
%T Electronic and Structural Relaxation of Photoexcited WO<sub>3</sub> Observed by Femtosecond Resonant X-ray Emission Spectra
%J The journal of physical chemistry letters
%V 16
%N 24
%@ 1948-7185
%C Washington, DC
%I ACS
%M PUBDB-2025-02025
%P 6138 - 6145
%D 2025
%X Photoexcited states of tungsten trioxide (WO<sub>3</sub>) were observed using femtosecond high-energy-resolution fluorescence detection X-ray Absorption Spectra (HERFD-XAS) and resonant X-ray emission spectra (RXES). In the initial state of the photoexcitation (∼100 fs), the W L<sub>3</sub> edge XAS shifts to lower energy and the energy levels of the t<sub>2g</sub> and e<sub>g</sub> peaks are modulated due to the photoexcited electrons in the conduction band. The electronic state of the photoexcited W atoms is modified by 500 fs. The crystal field splitting between the t<sub>2g</sub> and e<sub>g</sub> peaks shrinks by 500 fs, which indicates local structural changes around the W atoms due to the formation of polarons. HERFD-XAS and RXES provide more details about the early state of the photoexcited states of WO<sub>3</sub>. This work demonstrates that the detailed dynamics of 5d elements in the femtosecond range can be addressed with HERFD-XAS/RXES.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1021/acs.jpclett.5c01062
%U https://bib-pubdb1.desy.de/record/631513