Theoretical Study of Doubly Charged XH2O and XNH3 X = Si, Ge, Sn, Pb Molecular IonsReportar como inadecuado

Theoretical Study of Doubly Charged XH2O and XNH3 X = Si, Ge, Sn, Pb Molecular Ions - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Croatica Chemica Acta, Vol.82 No.1 June 2009. -

Ab initio calculations have been used to study the structure and stability of several doubly charged molecular ions in the gas phase. In particular the complexes of water and ammonia with Si2+, Ge2+, Sn2+ and Pb2+ have been studied. Geometries have been obtained at B3LYP-6-31Gd level and final energies at CCSDT-6-311+G3df,2p level. Different fragmentation channels have been considered. The loss of X+ X = Si, Ge, Sn, Pb is the most favorable one, except for SiH2O2+ where the loss of a H+ has a lower energy cost. Water complexes are thermodynamically stable, while loss of X+ in ammonia complexes are exothermic processes. In ammonia complexes a Coulomb barrier prevents the systems from spontaneous dissociation; to obtain these barriers the potential energy curves for the loss of Si+ or Pb+ in SiNH32+ and PbNH32+ complexes have been obtained at CCSDT-6-311+G3df,2p level, the corresponding vibrational states have been located and their lifetimes evaluated using the exterior complex scaling. The barriers for dissociation of XNH32+ complexes are similar to the ones obtained for XH2O2+ complexes.

DFT calculations; molecular ions; complexes; fragmentation; dissociation

Autor: Pablo López-Tarifa - ; Departamento de Química, C-9, Universidad Autónoma de Madrid, 28049 Madrid, Spain Fernando Martín - ;



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