title: Two distinctive energy migration pathways of monolayer molecules on metal nanoparticle surfaces.
abstract: Energy migrations at metal nanomaterial surfaces are fundamentally important to heterogeneous reactions. Here we report two distinctive energy migration pathways of monolayer adsorbate molecules on differently sized metal nanoparticle surfaces investigated with ultrafast vibrational spectroscopy. On a 5 nm platinum particle, within a few picoseconds the vibrational energy of a carbon monoxide adsorbate rapidly dissipates into the particle through electron/hole pair excitations, generating heat that quickly migrates on surface. In contrast, the lack of vibration-electron coupling on approximately 1 nm particles results in vibrational energy migration among adsorbates that occurs on a twenty times slower timescale. Further investigations reveal that the rapid carbon monoxide energy relaxation is also affected by the adsorption sites and the nature of the metal but to a lesser extent. These findings reflect the dependence of electron/vibration coupling on the metallic nature, size and surface site of nanoparticles and its significance in mediating energy relaxations and migrations on nanoparticle surfaces.
authors.affiliation: College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.|Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Jiebo
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Qian
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Hailong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Zhun
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Yuan
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Guangxu
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Miranda
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Xunmin
authors.initials: X
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
authors.forename: Yajing
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Nanfeng
authors.initials: N
authors.lastname: Zheng
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.|Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Wong
authors.affiliation: College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.|Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng