Tatiana Marchenko

CNRS UPMC · LCPMR

The natural widths of atomic resonances do not broaden spectral lines of emitted particles, which makes the corresponding spectroscopies suitable for high-resolution studies of x-ray absorption. While resonant inelastic x-ray scattering (RIXS) results in a narrow-band x-ray signal which primarily depends on the charge of the emitter, the resonant A...

The presence of doubly excited states (DESs) above the core-hole ionization threshold nontrivially modulates the x-ray absorption because the participator Auger decay couples DESs to the underlying low-energy core-hole continuum. We show that coupling also affects the high-energy continuum populated by the spectator Auger decay of DESs. For the K−L...

Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modelling, we identify significant structural dynamic...

We explore ultrafast charge transfer (CT) resonantly induced by hard x-ray radiation in organic thiophene-based polymers at the sulfur K-edge. A combination of core-hole clock spectroscopy with real-time propagation time-dependent density functional theory simulations gives an insight into the electron dynamics underlying the CT process. Our method...

High-resolution photoelectron spectra of xenon (Xe) were measured in the 4p photoionization region. The anisotropy parameters β were obtained for several photoelectron peaks with angle-resolved photoelectron measurements. The various complicated spectral features were observed due to the perturbed 4p−1 spin-orbit doublet and adjacent satellite stru...

We demonstrate experimentally and theoretically the presence of the post-collision interaction (PCI) effect in sulfur KL2,3L2,3 Auger electron spectra measured in the gas-phase thiophene and in solid-state organic polymers: polythiophene (PT) and poly(3-hexylthiophene-2,5-diyl), commonly known as P3HT. PCI manifests itself through a distortion and...

Momentum vector correlation is a powerful tool to study molecular dissociation. We have studied the three-body fragmentation of carbon disulfide after sulfur 1s photoionization is studied by means of momentum...

The photochemically induced ring-opening isomerization reaction of 1,3-cyclohexadiene to 1,3,5-hexatriene is a textbook example of a pericyclic reaction and has been amply investigated with advanced spectroscopic techniques. The main open question has been the identification of the single reactive state which drives the process. The generally accep...

Fragmentation dynamics of core-excited isolated ammonia molecules is studied by two different and complementary experimental methods, high-resolution resonant Auger spectroscopy and electron energy-selected Auger electron-photoion coincidence spectroscopy (AEPICO). The combined use of these two techniques allows obtaining information on different d...

Postcollision-interaction (PCI) effects involving multistep decay processes following Ar 1s photoionization has been studied by Auger electron spectroscopy. The experiment focused on LMM Auger electrons measured in small photon energy steps across the Ar 1s photoionization threshold. Decay pathways that we studied include (1) the Ar+*2p–1→Ar2+3p–2...

Resonant Auger electron spectroscopic study at the symmetry-forbidden [Formula: see text] excitation below the S [Formula: see text]-shell threshold of SF[Formula: see text] is reported. Partial electron yield and resonant [Formula: see text] Auger spectra have been measured by using monochromatized undulator synchrotron radiation. By changing the...

We propose a novel approach for an indirect probing of conjugation and hyperconjugation in core-excited molecules using resonant Auger spectroscopy. Our work demonstrates that the changes in the electronic structure of thiophene (C4H4S) and thiazole (C3H3NS), occurring in the process of resonant sulfur K-shell excitation and Auger decay, affect the...

Auger decay after photoexcitation or photoemission of an electron from a deep inner shell in the hard X-ray regime can be rather complex, implying a multitude of phenomena such as multiple-step cascades, post-collision interaction (PCI), and electronic state-lifetime interference. Furthermore, in a molecule nuclear motion can also be triggered. Her...

We study vibrationally-resolved resonant Auger (RAS) spectra of ammonia recorded in coincidence with the NH2+ fragment, which is produced in the course of dissociation either in the core-excited 1s-14a11 intermediate state or the first spectator 3a-24a11 final state. Correlation of the NH2+ ion flight times with electron kinetic energies allows dir...

The photochemically induced ring-opening isomerization reaction of 1,3-cyclohexadiene (CHD) to 1,3,5-hexatriene (HT) is a textbook example of a pericyclic reaction, and has been amply investigated with advanced spectroscopic techniques. The generally accepted description of the isomerization pathway starts with a valence excitation to the lowest-ly...

The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH 2 BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump — XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH 2 Br radicals...

The ultrafast structural dynamics of water following inner-shell ionization is a crucial issue in high-energy radiation chemistry. We have exposed isolated water molecules to a short x-ray pulse from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we can ima...

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH3I) by ultraintense (∼1019 W/cm2) x-r...

We have built an x-ray spectrometer in a von Hamos configuration based on a highly annealed pyrolytic graphite crystal. The spectrometer is designed to measure x-ray emission in the range of 2–5 keV. A spectral resolution E/ΔE of 4000 was achieved by recording the elastic peak of photons issued from the GALAXIES beamline at the SOLEIL synchrotron r...

Doppler and recoil effects are an integral part of the photoemission process at the high kinetic energies reached in hard x-ray photo-electron spectroscopy (HAXPES) and have a major effect on the observed lineshape, resulting in broadening, energy losses and discrete excitations. These effects can be modeled with a high degree of detail for small s...

Using synchrotron radiation in the tender X-ray regime, a photoelectron spectrum showing the formation of single site double-core-hole pre-edge states, involving the K shell of the O atom in CO, has been recorded by means of high-resolution electron spectroscopy. The experimentally observed structures have been simulated, interpreted and assigned,...

The photoionization branching ratios of spin–orbit doublets are studied both experimentally and theoretically at energies several keV above threshold. The results show significant relativistic effects for Ar 2p in the autoionizing region below the 1s threshold, and large many-body effects for Xe 3d and 4d in the vicinity of the L-shell thresholds....

A predictive understanding of soft x-ray near-edge absorption spectra of small molecules is an enduring theoretical challenge and of current interest for x-ray probes of molecular dynamics. We report the experimental absorption spectrum for the electron spectroscopy for chemical analysis (ESCA) molecule (ethyl trifluoroacetate) near the carbon 1s a...

State-of-the-art argon KLL Auger spectra measured using photon energies of hν = 3216 and 3400 eV are presented along with an Ar [1s] photoelectron spectrum (square brackets indicate holes in the respective orbital). The two different photon energies used for measuring the Auger spectra allow distinguishing between the shake transitions during the A...

We present a combined experimental and theoretical study of the double-core-hole photoelectron spectrum obtained in isolated water molecules irradiated with hard x-rays above the oxygen K ⁻² threshold. States of the type O K ⁻² V and multiply excited states are created by single-photon absorption and subsequent one-electron emission. A detailed ana...

A comprehensive electron spectroscopic study combined with partial electron yield measurements around the Br $1s$ ionization threshold of HBr at $\cong 13.482$ keV is reported. In detail, the Br $1s^{-1}$ x-ray absorption spectrum, the $1s^{-1}$ photoelectron spectrum as well as the normal and resonant $KLL$ Auger spectra are presented. Moreover, t...

We have observed formation of Rydberg series superimposed on the Ar (L3M2,3M2,3) Auger electron spectral profile with photoexcitation just above the 2p⁻¹3/2 photoionization threshold. This is due to the recapture of photoelectrons induced by post-collision interaction between the Auger electron and photoelectron: Ar⁺ 2p⁻¹3/2 + e⁻ → Ar⁺ 3p⁻²ml + e⁻....

We measured the Kr photoelectron spectrum in the region close to the 3p ionization threshold. Our high-resolution measurements allowed a clear observation of spectral structures due to electron correlation effects. Analysis based on relativistic multiconfiguration calculations could explain these observed peaks as due to strong configuration intera...

The 1s ⁻² Auger hypersatellite spectrum of argon is studied experimentally and theoretically. In total, three transitions to the final states 1s ⁻¹2p ⁻²(² S e ,² D e ) and 1s ⁻¹2s ⁻¹(¹ S)2p ⁻¹(² P o ) are experimentally observed. The lifetime broadening of the 1s ⁻² → 1s ⁻¹2p ⁻²(² S e ,² D e ) states is determined to be 2.1(4) eV. For the used phot...

Synopsis We demonstrate that the possibility of monitoring relative photoionization cross sections over a large photon energy range extending to hard x-rays allows studying and disentangling shake processes and intramolecular inelastic scattering effects. An “EXAFS”-type of oscillatory behaviour of the relative C 1 s cross sections is observed in a...

We present here a review of the most significant recent achievements in the field of HAXPES (HArd X-ray PhotoElectron Spectroscopy) on isolated atoms and molecules, and related spectroscopies. The possibility of conducting hard x-ray photoexcitation and photoionization experiments under state-of-the art conditions in terms of photon and electron ki...

We demonstrate that the possibility of monitoring relative photoionization cross sections over a large photon energy range allows studying and disentangling shake processes and intramolecular inelastic scattering effects. In this gas phase study, relative intensities of the C 1s photoelectron lines from chemically inequivalent carbon atoms in the s...

Young's double-slit-type interference from coherent electron emission is extended from two to several emitting centers in photoionization of complex polyatomic molecules.

Electron-ion coincidence experimental data obtained following argon 1s photoionization are reported. Slow photoelectrons were measured in coincidence with Ar+ and Ar2+ ions, and the β angular distribution parameter was obtained. The measured beta parameter for the Ar2+-photoelectron coincidence measurements shows a significant deviation from the β=...

The Si 1s⁻¹, Si 2s⁻¹, and Si 2p⁻¹ photoelectron spectra of the SiX4 molecules with X=F,Cl,Br,CH3 were measured. From these spectra the Si 1s⁻¹ and Si 2s⁻¹ lifetime broadenings were determined, revealing a significantly larger value for the Si 2s⁻¹ core hole of SiF4 than for the same core hole of the other molecules of the sequence. This finding is...

Observing and controlling molecular motion and in particular rotation are fundamental topics in physics and chemistry. To initiate ultrafast rotation, one needs a way to transfer a large angular momentum to the molecule. As a showcase, this was performed by hard X-ray C1s ionization of carbon monoxide accompanied by spinning up the molecule via the...

We present a combined experimental and theoretical study of the Auger-emission spectrum following double core ionization and excitation of gas-phase water molecules with hard-x-ray synchrotron radiation above the O K−2 threshold. We observe an indication of ultrafast proton motion occurring within the 1.5 fs lifetime of the double-core-hole (DCH) s...

The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both mol...

An accurate description of the interaction of intense hard X-ray pulses with heavy atoms, which is crucial for many applications of free-electron lasers, represents a hitherto unresolved challenge for theory because of the enormous number of electronic configurations and relativistic effects, which need to be taken into account. Here we report resu...

Spectra reflecting the formation of single-site double-core-hole pre-edge states involving the N 1s and C 1s core levels of acetonitrile have been recorded by means of high-resolution single-channel photoelectron spectroscopy using hard X-ray excitation. The data are interpreted with the aid of ab initio quantum chemical calculations, which take in...

A mixture of CF4 and CO gases is used to study photoelectron recoil effects extending into the tender x-ray region. In CF4, the vibrational envelope of the C 1s photoelectron spectrum becomes fully dominated by the recoil-induced excitations, revealing vibrational modes hidden from Franck-Condon excitations. In CO, using CF4 as an accurate energy c...

A new setup has been designed and built to study organometallic complexes in gas-phase at third generation Synchrotron radiation sources. This setup consists of a new home-made computer- controlled gas cell that allows to sublimate solid samples by controlling accurately the temperature. This cell has been developed to be part of the high resolutio...

Due to its element and site specificity, inner-shell photoelectron spectroscopy is a widely used technique to probe the chemical structure of matter. Here, we show that time-resolved inner-shell photoelectron spectroscopy can be employed to observe ultrafast chemical reactions and the electronic response to the nuclear motion with high sensitivity....

The application of a novel fast optical-imaging camera, TimepixCam, to molecular photoionization experiments using the velocity-map imaging technique at a free-electron laser is described. TimepixCam is a 256 × 256 pixel CMOS camera that is able to detect and time-stamp ion hits with 20 ns timing resolution, thus making it possible to record ion mo...

In many cases fragmentation of molecules upon inner-shell ionization is very unspecific with respect to the initially localized ionization site. Often this finding is interpreted in terms of an equilibration of internal energy into vibrational degrees of freedom after Auger decay. Here we investigate the x-ray photofragmentation of ethyl trifluoroa...

Complex decay pathways involving radiative and nonradiative relaxation after deep core-level ionization in argon are disentangled by a unique combination of several synchrotron radiation-based spectroscopic techniques. In particular, by comparing the results obtained from electron-ion coincidence, photon-ion coincidence, and x-ray emission measurem...

The first steps in photochemical processes, such as photosynthesis or animal vision, involve changes in electronic and geometric structure on extremely short time scales. Time-resolved photoelectron spectroscopy is a natural way to measure such changes, but has been hindered hitherto by limitations of available pulsed light sources in the vacuum-ul...

The formation of double core hole pre-edge states of the form $1s^{-1}2p^{-1}(^{1,3}\text{P})\sigmaup^*,n\ell$ for HCl, located on the binding energy scale as deep as 3 keV, has been investigated by means of a high resolution single channel electron spectroscopy technique recently developed for the hard x-ray region. A detailed spectroscopic assign...

Recent advances in X-ray instrumentation have made it possible to measure the spectra of an essentially unexplored class of electronic states associated with double inner-shell vacancies. Using the technique of single electron spectroscopy, spectra of states in CS2 and SF6 with a double hole in the K-shell and one electron exited to a normally unoc...

The dynamics following laser-induced molecular photodissociation of gas-phase CH$_{2}$BrI at 271.6 nm were investigated by time-resolved Coulomb explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH$_{2}$BrI undergoes C-I cleavage, depositing 65.6% of the available energy...

A combination of resonant inelastic x-ray scattering and resonant Auger spectroscopy provides complementary information on the dynamic response of resonantly excited molecules. This is exemplified for CH3I, for which we reconstruct the potential energy surface of the dissociative I 3d−2 double-core-hole state and determine its lifetime. The propose...

We present a comprehensive experimental and theoretical investigation on the LMM, LMN, and LNN normal Auger spectra of xenon, which reveal excellent agreement with theory when core-hole lifetimes of the two-hole final states are taken into account. Generally, the spectra turned out to be highly complex due to a strong overlap of the Auger transitio...

We present the hypersatellite Auger spectrum of neon which contains the decay transitions of the K−2, K−2V, K−2L−1, K−2L−1V, and K−1L−1V states. The Auger decays of these types of core-hole states show different line shapes and linewidths which can be distinguished due to the high experimental resolution available for the present experiments. The i...

X-ray free-electron lasers enable the investigation of the structure and dynamics of diverse systems, including atoms, molecules, nanocrystals and single bioparticles, under extreme conditions. Many imaging applications that target biological systems and complex materials use hard X-ray pulses with extremely high peak intensities (exceeding 10 20 w...

Tuning hard x-ray excitation energy along Cl 1 s → σ ∗ resonance in gaseous HCl allows manipulating molecular fragmentation in the course of the induced multistep ultrafast dissociation. The observations are supported by theoretical modeling, which shows a strong interplay between the topology of the potential energy curves, involved in the Auger...