Selective vibrational excitation in the resonant Auger decay following core-to- transitions in (original) (raw)
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Physical Review A, 2001
Resonant Auger spectra following the decay of doubly excited core states in N 2 in the range 409-411 eV have previously been assigned to ''atomic'' lines indicating ultrafast dissociation. Using high-resolution synchrotron radiation electron spectroscopy from the MAX II facility in Sweden we have remeasured the resonant Auger spectrum of N 2 in the vicinity of the N 1s threshold. Contrary to earlier studies, we find vibrational progressions that can be associated with the final C 2 ⌺ u ϩ and 2 2 ⌸ g states in N 2 ϩ. We conclude that the decay leads entirely to molecular final states.
The Journal of Chemical Physics, 2001
High-resolution Auger spectroscopy applied under resonant Auger Raman conditions is shown to be a powerful tool for characterizing complex potential energy surfaces in core-excited systems. Using the example of N t 1s Ϫ1 *→X 2 ⌸ resonant Auger transition in nitrous oxide we emphasize the interplay between the nuclear motion and the electronic decay. We show how the choice of excitation energy allows selection of core-excited species of different geometries. The nuclear dynamics of these species are mapped by measuring the resonant Auger decay spectra. In addition to the changes in vibrational structure observed for the resonant Auger decay spectra, a strong influence of nuclear motion on the electronic decay is revealed, inducing the so-called ''dynamical Auger emission.'' The experimental results are supported by ab initio quantum chemical calculations restricted to a linear geometry of the core-excited state.
2001
High-resolution Auger spectroscopy applied under resonant Auger Raman conditions is shown to be a powerful tool for characterizing complex potential energy surfaces in core-excited systems. Using the example of N t 1s Ϫ1 *→X 2 ⌸ resonant Auger transition in nitrous oxide we emphasize the interplay between the nuclear motion and the electronic decay. We show how the choice of excitation energy allows selection of core-excited species of different geometries. The nuclear dynamics of these species are mapped by measuring the resonant Auger decay spectra. In addition to the changes in vibrational structure observed for the resonant Auger decay spectra, a strong influence of nuclear motion on the electronic decay is revealed, inducing the so-called ''dynamical Auger emission.'' The experimental results are supported by ab initio quantum chemical calculations restricted to a linear geometry of the core-excited state.
Resonant broadening of quasi-atomic Auger spectra by elementary excitations
Journal of Physics C: Solid State Physics, 1983
The broadening of quasi-atomic lines in the cw and cc'v Auger spectra of solids is discussed and a new, resonant mechanism is proposed. Explicit expressions are derived that allow this resonant contribution to be computed directly from XPS and Auger spectra. The results are compared with other contributions arising from lifetime, dispersion and phonon broadening, with special reference to a series of transition metals. When certain conditions are met, as in the case of silver, the resonant broadening makes up a substantial contribution to the experimental linewidth.
Dissociation of core-valence doubly excited states in NO followed by atomic Auger decay
The Journal of Chemical Physics, 2010
The decay processes of core-valence doubly excited states near the N K edge of NO have been studied using electron spectroscopy. Electron yields measured as a function of photon energy and kinetic energy enable the clear identification of atomic Auger lines associated with the dissociation of doubly excited states. The atomic Auger lines exhibit Doppler profiles, allowing the entire reaction scheme of such dissociation processes to be determined.
2005
Vibrationally resolved spectra have been obtained for the lowest-lying cationic states X 2 B 1 , A 2 A 1 , and B 2 B 2 of the water molecule reached after participator resonant Auger decay of core-excited states. The angular distribution has been measured of the first four vibrational components of the X state in the photon energy regions including the O 1s → 4a 1 and the O 1s → 2b 2 core excitations, and for different portions of the vibrational envelope of the B state in the photon energy region including the O 1s→ 2b 2 core excitation. For the X state, a large relative spread in  values of the different vibrational components is observed across both resonances. For the B state, a very different trend is observed for the high binding energy side and the low binding energy side of the related spectral feature as a function of photon energy. A theoretical method based on the scattering K matrix has been used to calculate both the photoabsorption spectrum and the  values, by taking both interference between direct and resonant photoemission and vibrational/lifetime interference into account. The numerical results show qualitative agreement with the trends detected in the experimental values and explain the conspicuous variations of the  values primarily in terms of coupling between direct and resonant photoemission by interaction terms of different sign for different final vibrational states.
Theory of Auger spectra for molecular-field-split core levels
Physical Review A, 1996
A theory for nonradiative decay of molecular-field-split states is presented. It is shown that the relative inner-shell sublevel cross sections for Auger transitions are sensitively dependent on the matching of spin-orbit and molecular-field interactions. This can lead to suppression of particular sublevel Auger transitions and to a breakdown of the constant core-hole lifetime approximation. The investigated effects are caused by a strong dependence of the Auger intensity on the mutual local space orientation of initial-and final-state orbitals. These features are illustrated for S 2p ͑L II,III VV͒ Auger spectra of H 2 S, and explain the apparent mismatch of 2p spin-orbit energies observed in Auger and photoelectron spectra of this molecule.
Ramsey interferometry for resonant Auger decay through core-excited states
Physical Review A, 2016
We theoretically investigate the electron dynamics in Ne atoms involving core-excited states through the Ramsey scheme with a pair of time-delayed x-ray pulses. Irradiation of Ne atoms by the ∼1 femtosecond x-ray pulse simultaneously populates two core-excited states, and an identical but time-delayed x-ray pulse probes the dynamics of the core-excited electron wave packet which is subject to the resonant Auger decay. The energy-integrated total Auger electron yield and energy-resolved Auger electron spectra in the time domain show periodic structures due to the temporal evolution of the wave packet, from which we can obtain the counterpart in the frequency domain through the Fourier transformation. The Auger electron energy spectra in the time as well as frequency domains show the interference patterns between the two Auger electron wave packets released into the continuum from the superposition of two core-excited states at different times. These spectra are important to clarify the individual contribution of the different Auger decay channels upon core excitation by the x-ray pulse.
Interference through the resonant Auger process via multiple core-excited states
Physical Review A, 2017
We theoretically investigate the resonant Auger process via multiple core-excited states. The presence of multiple core-excited states sets off interference into the common final continuum, and we show that the degree of interference depends on the various parameters such as the intensity of the employed x-ray pulse and the lifetimes of the core-excited states. For the specific examples we employ the double (1s −1 3p and 1s −1 4p) core-excited states of Ne atom and numerically solve the time-dependent Schrödinger equation to demonstrate that the energy-resolved electron spectra clearly exhibit the signature of interference.