Raw Raman spectrum of gibbsite powder.
Hydrogen (1–6) and aluminum (I–II) notations. (001) view of gibbsite.
DRIFT spectrum of a gibbsite sample in the O–D stretching region (D in natural abundance, i.e., 0.015% of H atoms).
The two-layer gibbsite model used throughout the study.
The two possible water adsorption configurations. (a) Water molecule is linked to two surface hydrogen atoms. (b) Water molecule is linked to only one surface hydrogen atom. (c) The four kinds of adsorption sites are illustrated: in-plane H atoms are surrounded in yellow; out-of-plane ones are surrounded in purple. Blue circles: water molecule is linked to two surface hydrogen atoms [see Fig. 5(a)]. Green dash circles: water molecule is linked to only one surface hydrogen atom [see Fig. 5(b)]. Two sites are related to the presence of a sublayer aluminum atom. (d) One of the three possible monolayer coverages of the (001) plane of gibbsite. The black rectangle represents the unit cell. The two water molecules configurations appear within red circle (one out-of-plane H atom: 0.63 eV) and blue dot circle (two out-of-plane H atoms: 0.45 eV).
The three possible sites for uranyl adsorption.
The most stable calculated complex. Hydrogen bonds are in black dash lines; water molecules are in circles. (a) Top view and (b) side view.
Difference Raman spectrum of adsorbed uranyl cations at a value of 4. The difference corresponds to the subtraction of the Raman spectrum obtained after adsorption by the initial sample spectrum.
Fluorescence spectra of uranyl sorbed onto gibbsite for two delays after the laser pulse [(a) and (c) ] and (b) in aqueous solution.
Experimental wavenumbers of OD stretching modes and deduced harmonic wavenumbers used in this paper to estimate the OH(D) distances since the values deduced from the XRD measurements are not adequate.
Calculated and experimental gibbsite bulk parameters.
Bond lengths of uranyl cation with five water molecules: Comparison of DFT calculations with experimental EXAFS data obtained in acidic aqueous solution. Distances are in and angles are in degree.
Characteristics of the adsorbed complexes (distances and relative energy) with respect to the surface protonation state. Distances are in .
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