Chemical analysis: Double core-hole spectroscopy with free-electron lasers

Abstract

 Free-electron lasers have enabled chemical analysis of similar molecules due to their femtosecond pulse duration, high pulse energy and tunable photon energy in the -x-ray regime  We have exploited the attributes of these new lasers by exploring intriguing non-linear effects such as double core-hole formation. Multiphoton absorption is key to the observation of double core-holes in atoms and molecules . We have carried out x-ray two-photon photoelectron spectroscopy for molecular chemical analysis using the Linac Coherent Light Source. Our experimental work validated the theory of two-photon photoelectron spectroscopy. This work demonstrates that our methodology will be very effective with the future intense, high repetition rate as well as laser-seeded or self-seeded photon facilities. AbstractFree-electron lasers with their femtosecond pulse duration, high pulse energy and tunable photon energy in a regime from XUV to hard-x-ray have opened up several research avenues in physics, chemistry and biology. We have exploited the attributes of these new lasers by exploring intriguing non-linear effects such as double core-hole formation via multiphoton absorption. We have carried out x-ray two-photon photoelectron spectroscopy for molecular chemical analysis using the Linac Coherent Light Source. Our experimental work aimed to probe the chemical environment of specific atomic sites in several molecules and validate the theory of two-photon photoelectron spectroscopy. This work demonstrates that our methodology will be very effective with the future intense, high repetition rate as well as laser-seeded or self-seeded photon facilities.

Multi-electron coincidence spectroscopy: double photoionization from molecular inner-shell orbitals

“…In this review we will summarize the progress recently achieved in these different subjects, and extend the previous reviews that have already been published on the subject [5][6][7][8][9].…”

Short-wavelength free-electron laser sources and science: a review

“…Double core-hole creation in molecules [342,343] has received attention in part because of its potential application to chemical analysis [344][345][346]. X-ray two-photon photoelectron spectroscopy and partial covariance mapping of two core-level photoelectrons have been used to investigate double core-hole states of some small molecules and this has provided a proof-ofprinciple confirmation for the high sensitivity of double core-hole spectroscopy to the chemical environments of specific two atomic sites whose core electrons have been ejected [311,[347][348][349][350]. That DCH spectroscopy provides a sensitive test of chemical environment has implications for single-pulse imaging of biomolecules described above as well as on work on solids described below.…”

Advanced Computation Method for Double Core Hole Spectra: Insight into the Nature of Intense Shake-up Satellites

“…Thanks to experimental and theoretical development, double core shell photoionization had a continuously growing attractivity for the past decade. The current generation of X-ray sources finally allowed to observe the formation of doubly core ionized molecular system consecutive to either the interaction with a single X-ray photon, using syn-chrotron radiation [11], or to a sequential absorption of two X-ray photons, by mean of X-FEL radiation [12]. The early theoretical work of Cederbaum et.…”