[1] Imperial Coll London, Dept Mat, South Kensington Campus, London SW7 2AZ, England
[2] Friedrich Schiller Univ Jena, Otto Schott Inst Mat Res, D-07743 Jena, Germany
[3] Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Porthansgatan 3, FI-20500 Turku, Finland
[4] Spinode Consulting, 801 Brandywine Court, St Augustine, FL 32086 USA