RadChem 2014

Theoretical Chemistry Study of Uranyl (VI)-Sulphate complex species

13 May 2014, 17:15

1h 30m

Casino Conference Centre

Poster Chemistry of Actinide and Trans-actinide Elements Poster Session - Chemistry of Actinide and Trans-actinide Elements

Speaker

Mr Jakub Visnak (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague)

Description

This theoretical study of several possible complex species of the general formula ([UO${}_2$(H${}_2$O)${}_a$(${\eta }^1$-SO${}_4$)${}_b$(${\eta }^2$-SO${}_4$)${}_c$]${}^{2-2(b+c)},0\le b+c\le 4,5\le a+b+2c\le 6,[UO$_2$(H$_2$O)$_2$($\eta^1$-SO$_4$)($\eta^2$-SO$_4$)]$^{2-}$depictedattheFig.1.)aspirestothetheoreticalpredictionofstabilityconstants$\beta$°,thermodynamicalproperties(i.e.$\Delta$G°and$\Delta$H°)andtheirdependanceonthetemperature.Equilibriumgeometriesinthegroundstateandseveralexcitedelectronicstates,vibrationalmodesandfrequencies,momentsofinertia,verticaltransitionenergiesimportanttotheUV-VISabsorption,excitationandemission/fluorescencespectrawerecalculatedaswell.Ourstudyisalsothefirststeptowardsthemolecular-dynamicalstudysearchingseekingforanotherapproachtopredict$\Delta$G°,$\Delta$H°andlog$\beta$° and, more importantly, to predict the fluorescence lifetimes (or more generaly - the TRLFS spectra) and their dependance on the temperature and ionic strength (or, more generaly - the solution composition). The comparison of all of the ab initio predicted and experimentally obtained quantities is included. Both, the purely ab initio methods based on the Dirac(-Breit) equation (DHF, MCDHF, KRCI, CCSD) and the density functional methods (DFT (b3-lyp/def-SVP), TDDFT (bh-lyp/def-SVP)) were used. This work tries to reproduce and further develop the study of uranyl-sulfates done by Jakub Šebera [1].