RT Journal Article T1 Visualizing coherent vibrational motion in the molecular iodine B state using ultrafast XUV transient-absorption spectroscopy A1 Marggi Poullaín, Sonia A1 Kobayashi, Yuki A1 Chang, Kristina A1 Leone, Stephen AB Attosecond probing of core-level electronic transitions in molecules provides a sensitive tool for real-time observation of chemical dynamics. Here, we employ ultrafast extreme-ultraviolet (XUV) transient-absorption spectroscopy to investigate the excited state electronic and nuclear dynamics in a prototype molecule, I2. A few-femtosecond visible pump pulse is employed to excite the I2 molecule and an attosecond XUV pulse is used to probe the dynamics through iodine-4d core-to-valence transitions. A highly extended vibrational wave packet (ν′=10–50,ν′max=25) is prepared by one-photon absorption in the valence excited B3Π0+u state of I2 and its motion is directly mapped due to the strong shift of the XUV core-level transition with internuclear separation. Through the imaging of this vibrational motion, we directly reconstruct the transition energy between the valence and the core-excited states as a function of internuclear distance. Besides single-photon dynamics, distinct direct dissociation pathways arising from two-photon pump absorption are also revealed. PB American Physical Society SN 2469-9926 YR 2021 FD 2021 LK https://hdl.handle.net/20.500.14352/92998 UL https://hdl.handle.net/20.500.14352/92998 LA eng NO Poullain, Sonia M., et al. «Visualizing Coherent Vibrational Motion in the Molecular Iodine B 3 Π 0 + u State Using Ultrafast XUV Transient-Absorption Spectroscopy». Physical Review A, vol. 104, n.o 2, agosto de 2021, p. 022817. https://doi.org/10.1103/PhysRevA.104.022817. DS Docta Complutense RD 8 jul 2025