Imaging charge transfer in iodomethane upon x-ray photoabsorption

Abstract

Studies of charge transfer are often hampered by difficulties in determining the charge localization at a given time. Here, we used ultrashort x-ray free-electron laser pulses to image charge rearrangement dynamics within gas-phase iodomethane molecules during dissociation induced by a synchronized near-infrared (NIR) laser pulse. Inner-shell photoionization creates positive charge, which is initially localized on the iodine atom. We map the electron transfer between the methyl and iodine fragments as a function of their interatomic separation set by the NIR-x-ray delay. We observe signatures of electron transfer for distances up to 20 angstroms and show that a realistic estimate of its effective spatial range can be obtained from a classical over-the-barrier model. The presented technique is applicable for spatiotemporal imaging of charge transfer dynamics in a wide range of molecular systems.

Ultrafast isomerization initiated by X-ray core ionization

“…These light sources have been employed for molecular and material science, as well as structural biology [5][6][7][8][9][10][11][12][13][14][15] . Current and future X-ray FELs plan to deliver ultrashort X-ray pulses with sufficiently high intensity to collect diffraction images of selected targets in a single shot.…”

Ultrafast x-ray-induced nuclear dynamics in diatomic molecules using femtosecond x-ray-pump–x-ray-probe spectroscopy

“…Molecular ionization and fragmentation follow absorption of a single synchrotron x ray [33][34][35] or absorption of multiple x rays using XFEL radiation [36][37][38][39][40]. In the present experiment, we exploited the femtosecond time resolution of XFEL pulses, but the fluences of the pump and probe pulses were designed to observe singlephoton pump and single-photon probe events.…”

A soft X-ray free-electron laser beamline at SACLA: the light source, photon beamline and experimental station

“…The advent of X-ray free-electron lasers (XFELs) has stimulated marked progress in various scientific fields, such as ultrafast chemistry (Moshammer et al, 2007;Erk et al, 2014), nonlinear X-ray optics (Rohringer et al, 2012;Glover et al, 2012;Bencivenga et al, 2015) and structural biology (Boutet et al, 2012;Nango et al, 2016). The first FEL operation in the extreme ultraviolet (EUV) region was achieved by the TESLA Test Facility (TTF; Andruszkow et al, 2000) at DESY, Germany, in 2000, which was later renamed FLASH (Ackermann et al, 2007).…”