Density functional theory based molecular dynamics study of hydration and electronic properties of aqueous La(3+).
Structural and electronic properties of La(3+) immersed in bulk water have been assessed by means of density functional theory (DFT)-based Car-Parrinello molecular dynamics (CPMD) simulations. Correct structural properties, i.e., La(III)-water distances and La(III) coordination number, can be obtained within the framework of Car-Parrinello simulations providing that both the La pseudopotential and conditions of the dynamics (fictitious mass and time step) are carefully set up. DFT-MD explicitly treats electronic densities and is shown here to provide a theoretical justification to the necessity of including polarization when studying highly charged cations such as lanthanoids(III) with classical MD. La(3+) was found to strongly polarize the water molecules located in the first shell, giving rise to dipole moments about 0.5 D larger than those of bulk water molecules. Finally, analyzing Kohn-Sham orbitals, we found La(3+) empty 4f orbitals extremely compact and to a great extent uncoupled from the water conduction band, while the 5d empty orbitals exhibit mixing with unoccupied states of water.
Terrier
Cyril
C
Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, CNRS UMR 8587, Université d'Evry Val d'Essonne, Boulevard F. Mitterrand, 91025 Evry Cedex, France.
Vitorge
Pierre
P
Gaigeot
Marie-Pierre
MP
Spezia
Riccardo
R
Vuilleumier
Rodolphe
R
D002412:Cations / Q000737:chemistry; D004581:Electronics; D007811:Lanthanum / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D013057:Spectrum Analysis; D014867:Water / Q000737:chemistry*
D002412:Cations; D014867:Water; D007811:Lanthanum