title: Communication: Chemisorption of muonium on gold nanoparticles: A sensitive new probe of surface magnetism and reactivity.
abstract: Chemisorption of muonium onto the surface of gold nanoparticles has been observed. Muonium (μ+e-), a light hydrogen-like atom, reacts chemically with uncapped 7 nm gold nanoparticles embedded in mesoporous silica (SBA-15) with a strong temperature-dependent rate. The addition rate is fast enough to allow coherent spin transfer into a diamagnetic muon state on the nanoparticle surface. The muon is well established as a sensitive probe of static or slowly fluctuating magnetic fields in bulk matter. These results represent the first muon spin rotation signal on a nanoparticle surface or any metallic surface. Only weak magnetic effects are seen on the surface of these Au nanoparticles consistent with Pauli paramagnetism.
authors.affiliation: Physik-Department, Technische Universität München, James-Franck-Strasse 1, 85748 Garching bei München, Germany.
authors.forename: M H
authors.initials: MH
authors.lastname: Dehn
authors.affiliation: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors.forename: D J
authors.initials: DJ
authors.lastname: Arseneau
authors.affiliation: Physik-Department, Technische Universität München, James-Franck-Strasse 1, 85748 Garching bei München, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Böni
authors.affiliation: Jules Stein Eye Institute, 100 Stein Plaza UCLA, Los Angeles, California 90095, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Bridges
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Buck
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: D L
authors.initials: DL
authors.lastname: Cortie
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: D G
authors.initials: DG
authors.lastname: Fleming
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Kelly
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: W A
authors.initials: WA
authors.lastname: MacFarlane
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: MacLachlan
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: R M L
authors.initials: RM
authors.lastname: McFadden
authors.affiliation: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors.forename: G D
authors.initials: GD
authors.lastname: Morris
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: P-X
authors.initials: PX
authors.lastname: Wang
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Institute of Chemistry, University of Sao Paulo, Avenida Professor Lineu Prestes 748, Sao Paulo, CEP 05508-000, Brazil.
authors.forename: V M
authors.initials: VM
authors.lastname: Zamarion
authors.affiliation: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors.forename: R F
authors.initials: RF
authors.lastname: Kiefl