title: Superatom State-Resolved Dynamics of the Au25(SC8H9)18(-) Cluster from Two-Dimensional Electronic Spectroscopy.
abstract: Superatom state-resolved dynamics of the Au25(SC8H9)18(-) monolayer-protected cluster (MPC) were examined using femtosecond two-dimensional electronic spectroscopy (2DES). The electronic ground state of the Au25(SC8H9)18(-) MPC is described by an eight-electron P-like superatom orbital. Hot electron relaxation (200 ± 15 fs) within the superatom D manifold of lowest-unoccupied molecular orbitals was resolved from hot hole relaxation (290 ± 20 fs) in the superatom P states by using 2DES in a partially collinear pump-probe geometry. Electronic relaxation dynamics mediated by specific superatom states were distinguished by examining the time-dependent cross-peak amplitudes for specific excitation and detection photon energy combinations. Quantification of the time-dependent amplitudes and energy positions of cross peaks in the 2.21/1.85 eV (excitation/detection) region confirmed that an apparent energetic blue shift observed for transient bleach signals results from rapid hot electron relaxation in the superatom D states. The combination of structurally precise MPCs and state-resolved 2DES can be used to examine directly the influence of nanoscale structural modifications on electronic carrier dynamics, which are critical for developing nanocluster-based photonic devices.
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Stoll
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Sgrò
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306-4390, United States.
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Jarrett
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.|Paul Scherrer Institute , CH-5232 Villigen PSI, Switzerland.
authors.forename: Julien
authors.initials: J
authors.lastname: Réhault
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Oriana
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Sala
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Branchi
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Cerullo
authors.affiliation: IFN-CNR, Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, 20133 Milano, Italy.|Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306-4390, United States.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Knappenberger