Theory of polarization-averaged core-level molecular-frame photoelectron angular distributions: III. New formula for p- and s-wave interference analogous to Young’s double-slit experiment for core-level photoemission from hetero-diatomic molecules

Abstract

We present a new variation of Young's double-slit formula for polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) of hetero-diatomic molecules, which may be used to extract the bond length. So far, empirical analysis of the PA-MFPADs has often been carried out employing Young's formula in which each of the two atomic centers emits a s-photoelectron wave. The PA-MFPADs, on the other hand, can consist of an interference between the p-wave from the X-ray absorbing atom emitted along the molecular axis and the s-wave scattered by neighboring atom, within the framework of Multiple Scattering theory. The difference of this p-s wave interference from the commonly used s-s wave interference causes a dramatic change in the interference pattern, especially near the angles perpendicular to the molecular axis. This change involves an additional fringe, urging us to caution when using the conventional Young's formula for retrieving the bond length. We have derived a new formula analogous to Young's formula but for the p-s wave interference. The bond lengths retrieved from the PA-MFPADs via the new formula reproduce the original C-O bond lengths used in the reference ab-initio PA-MFPADs within the relative error of 5 %. In the high energy regime, this new formula for p-s wave interference converges to the ordinary Young’s formula for the s-s wave interference. We expect it to be used to retrieve the bond length for time-resolved PA-MFPADs instead of the conventional Young's formula.

State‐selected photo‐recombination cross sections of H‐like ions in the KLL resonant energy range

“…Table 2 shows that the transition probabilities obtained from two gauges agree well with each other, and our results are consistent with those given in references for both the transition energies and probabilities. Using these results, we are able to identify all resonance peaks in each partial PR profile and label them with atomic state notations in Figures 1,2,3,4,5,6,and 7. As shown in the figures, the resonant peaks become farther apart as the nuclear number increases. This phenomenon is caused by greater spin-orbit-interaction splitting in higher-Z ions, which can enable easier identifications of the resonant peaks in experiments.…”

“…photoionization process [2][3][4][5] as well as between some direct and indirect atomic processes involved in the electron-ion recombination [6][7][8][9][10][11] and photon-ion ionization [12]. In the plasma environment, PR is an important recombination process and has gained significant attention in interferometry studies.…”

Single-photon ionization of aligned H 2+ with near-ionization-threshold photon energy

“…Different from the case of the high-intensity and low-frequency laser field where the mechanism of tunneling ionization dominates, the ionization of atoms or molecules in a low-intensity and high-frequency laser field is dominated by single-photon ionization. For a diatomic molecule or molecular ion with two atomic centers, such as N 2 [24][25][26][27], H 2 [28][29][30][31][32], H + 2 [33,34], O 2 [35], O 2+ 2 [36], Ne 2 [37], CO [38,39], and CO 2+ [40][41][42], during the process of single-photon ionization, the emitting electronic wave with real momentum interferes between these two atomic centers of the molecule. This phenomenon can be understood as the molecular-level double-slit interference.…”

Time-Resolved Resonant Auger Scattering Clocks Distortion of a Molecule

“…The development of ultrashort X-ray free electron laser sources (XFELs) has enabled new types of pump–probe techniques. − Molecules excited by the pump pulse can undergo large distortion from their initial geometry, whereby their combined nuclear and electronic dynamics of valence and core excited states can be probed by techniques that involve core hole states reached by an X-ray probe pulse. Different detection schemes have been put forward: Coulomb explosion imaging, , X-ray diffraction, , X-ray photoelectron spectroscopy, − X-ray photoelectron diffraction, − AES, X-ray transient absorption detecting hole states, , and X-ray control of RAS . For the X-ray photoelectron spectroscopy, the use of femtosecond to attosecond X-ray pulses guarantees high temporal resolution, but its broad energy width would wash out the fine vibrational structures reflecting the nuclear dynamics; − in addition, the photoelectrons emitted from the ground state creating the background signal would tangle with electron signals from the valence excited state of interest.…”