Structure and Spectra of UO₂F₂ and Its Hydrated Species

Abstract

The electronic spectra of UO2F2, both isolated and hydrated, have been studied using ab initio spin−orbit configuration interaction calculations based on relativistic effective core potentials. The structures of UO2F2 species were obtained by the density functional theory method. The initial structure has a (nonplanar) C 2 v geometry, while adding solvating water molecules and optimizing the structure UO2F2(H2O) n give a very stable structure for n = 4, with D 2 geometry. The ground state and some excited states were studied for UO2F2(H2O) n using the structures obtained. Electric-dipole transition moments were calculated for UO2F2(H2O)4. Spin−orbit and equatorial−ligand (F-, H2O) interactions compete in determining the splittings of the known 3Δg state of the uranyl ion, particularly the 3Δ1g luminescent state.

Electronic spectra of uranyl chloride complexes in acetone: a CASSCF/CASPT2 investigation

“…We finally note that the calculated values of the oscillator strengths in this work are of the same order of magnitude (10 À8 to 10 À5 ) as previous results obtained with SOC-CI for UO 2 F 2 . 13…”

“…1,2 Still, many details of its electronic structure are unrevealed and, as the number of recent publications on UO 2 2+ demonstrates, the debates continue up to now. [3][4][5][6][7][8][9][10][11][12][13] Detailed quantum chemical calculations on the electronic structure and spectrum of UO 2 2+ have only recently become possible, thanks to the increasing computer power and the development of appropriate algorithms for the inclusion of relativistic effects.…”

A Theoretical Study of the Structure and Bonding of UOX4(X=F, Cl, Br, I) Molecules: The Importance of InverseTransInfluence

“…[3,7] The lower energy of the p orbitals reflects well the strength of these interactions with respect to the s UÀO bonds. Isoelectronic uranyl analogues ZUZ' n + (Z, Z' = O, N; n = 0, 1) [6,7,[10][11][12][13][14][15][16] and uranyl compounds with the general formula UO 2 X 2 (X = F, Cl, Br, I, OH) [17][18][19][20] all showed preference for a linear ZUZ' (slightly deformed in UO 2 X 2 ) arrangement. The study of the triple-bond character of the UZ bond was not a focus of investigations, but has also been reported in a few cases.…”

“…Isoelectronic uranyl analogues ZUZ′ n + (Z, Z′=O, N; n =0, 1)6, 7, 10–16 and uranyl compounds with the general formula UO 2 X 2 (X=F, Cl, Br, I, OH)17–20 all showed preference for a linear ZUZ′ (slightly deformed in UO 2 X 2 ) arrangement. The study of the triple‐bond character of the UZ bond was not a focus of investigations, but has also been reported in a few cases 6.…”

A Comparative Relativistic DFT and Ab Initio Study on the Structure and Thermodynamics of the Oxofluorides of Uranium(IV), (V) and (VI)

“…Wang and Pitzer [22] calculated the ground and excited states of UO 2 F 2 ; for the ground state, the LDA geometry has been used. The molecule was of C 2v symmetry, with an F-U-F angle of 109.68, and an O=U=O angle slightly distorted from linearity, as 169.58.…”