Effects of solvation shells and cluster size on the reaction of aluminum clusters with water
Weiwei Mou,
Satoshi Ohmura,
Anne Hemeryck,
Fuyuki Shimojo,
Rajiv K. Kalia,
Aiichiro Nakano,
Priya Vashishta
Affiliations
Weiwei Mou
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Satoshi Ohmura
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Anne Hemeryck
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Fuyuki Shimojo
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Rajiv K. Kalia
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Aiichiro Nakano
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Priya Vashishta
Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242, USA
Reaction of aluminum clusters, Aln (n = 16, 17 and 18), with liquid water is investigated using quantum molecular dynamics simulations, which show rapid production of hydrogen molecules assisted by proton transfer along a chain of hydrogen bonds (H-bonds) between water molecules, i.e. Grotthuss mechanism. The simulation results provide answers to two unsolved questions: (1) What is the role of a solvation shell formed by non-reacting H-bonds surrounding the H-bond chain; and (2) whether the high size-selectivity observed in gas-phase Aln-water reaction persists in liquid phase? First, the solvation shell is found to play a crucial role in facilitating proton transfer and hence H2 production. Namely, it greatly modifies the energy barrier, generally to much lower values (< 0.1 eV). Second, we find that H2 production by Aln in liquid water does not depend strongly on the cluster size, in contrast to the existence of magic numbers in gas-phase reaction. This paper elucidates atomistic mechanisms underlying these observations.
