Au–Xe REMPI spectrum in the region of the , transition observed by gating on all isotopologues (uppermost spectrum) and for individual isotopologues (lower spectra). The spectra have not been corrected for variations in laser pulse energy which decreases toward the red of the spectrum.
The spectrum in the region of the Au–Xe , transition as observed in the mass channel and the mass channel. peaks labeled with asterisks result from fragmentation and the sharp feature at is the atomic transition. The highlighted region of the level is examined in greater detail in Fig. 4.
(Inset) The gold atom fragment image observed following excitation of the Au–Xe level. The left hand side shows the raw image, while the right hand side shows the result of the image reconstruction. The smaller less-well resolved ring at the center of the image are Au atoms produced in direct dissociation of Au–Ar which is produced simultaneously with Au–Xe. (Main figure) The extracted total kinetic energy release (TKER) spectra observed by imaging the Au fragment upon excitation of each Au–Xe level. Extrapolation to confirms that predissociation occurs to the channel.
(a) The Au–Xe (14,0) transition as observed in the , , , , and channels. Fits to Fano line profiles (in red online) are shown slightly offset for clarity. (b) Overlay of the Au–Xe (14,0) transition (all isotopologues) observed in the REMPI channel (blue) and dissociation channel (black). The extracted Fano profile -parameters (red points) follow the observed reduction in signal.
Gold atom fragment TKER vs photolysis wavenumber for Au–Xe photodissociation via the transitions (◻), as well as for Au–Ar (◼) and Au–Kr (◇) direct dissociation to the continuum. The dashed lines show linear fits to the observed data. Solid lines show the TKER dependence expected for dissociation at the two- and three-photon level.
The spectral region as observed in REMPI channel (top) and dissociation channel (bottom). The intense feature observed at (marked with ) is due to detector saturation at the Au REMPI transition. signal above can be attributed to fragmentation of Au–Ar to the continuum and to fragmentation of . (Inset spectrum) REMPI spectrum observed when gating on the Au ring corresponding to Au–Ar photodissociation. (Inset images) Au images from Au–Ar photolysis at selected wavenumbers in the continuum. The central features in the VMI images arising from metastable gold atoms in the beam have been removed for clarity.
(a) Radial spectra extracted from Au fragment images following Au–Kr and Au–Ar photodissociation via the dissociative continuum. The peaks due to Au fragments from Au–Kr and Au–Ar grow at different rates with excitation wavenumber due to the kinematics of the recoil. The central ( radius) features in the VMI images arising from gold atoms in the beam have been removed for clarity. (b) Au atom fragment images observed for Au–Kr direct photodissociation via the state dissociative continuum at . (c) and (d) .
(a) Summary of photolysis processes observed for Au–Xe (black), Au–Kr (blue), and Au–Ar (red) in the spectral region. (b) Qualitative potential energy curve in the region of the Au–Xe level (highlighted with a green box in (a).
to signal ratios following excitation to the Au–Xe (8–14,0) transitions. Ratios were determined by integrating each signal across the isotopologue profile of the given peak. The branching ratios for predissociation of the into the and product channels were derived from the VMI results.
Fano profile fit parameters for the Au–Xe (14, 0) transitions (see text).
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