Chemistry Reference
In-Depth Information
(A)
(B)
(C)
(D)
FIGURE 4.1 (See color insert.)  Illustration.of.proton.transfer.in.water.around.Fe 3+ .ions.and.
Cr 3+ .ions.from.CPMD/TPS.simulations..Many.water.molecules.are.deleted.to.clearly.show.the.
molecular.mechanism..See.text.for.discussion.of.mechanism..Illustration.of.the.mechanism.
of. water. dissociation. around. metal. (Cr 3+ ,. Fe 3+ ). ions. which. begins. with. a. slightly. elongated.
O-H.bond.(A)..Proton.migration.leads.to.the.hydroxylation.of.the.metal.ion.(B)..Movement.
of.a.proton.into.the.second.solvation.shell.leads.to.the.formation.of.a.Zundel.complex.(C)..
Further.proton.transfer.leads.to.the.formation.of.an.Eigen.complex.(D)..(Coskuner,.O..et.al.,.
Water Dissociation in the Presence of Metal Ions ,.7853,.2007..Copyright.Wiley-VCH.Verlag.
GmbH.&.Co..KGaA..Reproduced.with.permission.)
detailed.electronic.structure.information.afforded.by.irst.principles.methods.such.
as.many.body.interactions.[60,61]..CPMD.simulations.of.Be 2+ .in.water.have.dem-
onstrated.the.advantages.of.including.many.body.interactions.in.the.dynamics.of.
metal..solutions.[41,61-64].
The.migration.of.a.proton.in.water.and.the.migration.of.OH .in.water.have.also.
been. simulated.. It. was. shown. that. proton. migration. is. a. topological defect . in. the.
hydrogen. bond. network. rather. than. a. single. proton. that. migrates. though. the. net-
work.[41]..The.notion.of.“structural.diffusion”.mentioned.above.is.used.to.describe.
this.topological.defect.mechanism.that.includes.the.breaking.and.forming.of.O-H.
bonds..AIMD.simulations.of.the.proton.in.water.showed.that.both.Eigen.and.Zundel.
complexes. are. observed. in. the. structural. diffusion. molecular. mechanism.. These.
Search WWH ::




Custom Search