Femtosecond M-2,M-3-Edge Spectroscopy of Transition-Metal Oxides: Photoinduced Oxidation State Change in alpha-Fe2O3

Josh Vura-Weis; Chang-Ming Jiang; Chong Liu; Hanwei Gao; J. Matthew Lucas; Frank M. F. de Groot; Peidong Yang; A. Paul Alivisatos; Stephen R. Leone

doi:10.1021/jz401997d

Femtosecond M-2,M-3-Edge Spectroscopy of Transition-Metal Oxides: Photoinduced Oxidation State Change in alpha-Fe2O3

Josh Vura-Weis, Chang-Ming Jiang, Chong Liu, Hanwei Gao, J. Matthew Lucas, Frank M. F. de Groot, Peidong Yang, A. Paul Alivisatos, Stephen R. Leone^*

^*Corresponding author for this work

Sub Inorganic Chemistry and Catalysis

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Oxidation-state-specific dynamics at the Fe M-2,M-3-edge are measured on the sub-100 fs time scale using tabletop high-harmonic extreme ultraviolet spectroscopy. Transient absorption spectroscopy of alpha-Fe2O3 thin films after 400 nm excitation reveals distinct changes in the shape and position of the 3p -> valence absorption peak at similar to 57 eV due to a ligand-to-metal charge transfer from 0 to Fe. Semiempirical ligand field multiplet calculations of the spectra of the initial Fe3+ and photoinduced Fe2+ state confirm this assignment and exclude the alternative d-d excitation. The Fe2+ state decays to a long-lived trap state in 240 fs. This work establishes the ability of time-resolved extreme ultraviolet spectroscopy to measure ultrafast charge-transfer processes in condensed-phase systems.

Original language	English
Pages (from-to)	3667-3671
Number of pages	5
Journal	Journal of Physical Chemistry Letters
Volume	4
Issue number	21
DOIs	https://doi.org/10.1021/jz401997d
Publication status	Published - 7 Nov 2013

Funding

J.V.-W. and S.R.L. acknowledge support from The Office of Assistant Secretary of Defense for Research and Engineering, NSSEFF. Initial work by J.V.-W. was supported by the NSF ACC-F Postdoctoral Fellowship. Initial work by C.-M.J. was supported by the NSF Extreme Ultraviolet Engineering Resource Center for Extreme Ultraviolet Research and Technology (EEC-0310717). A.P.A., C.L., C.-M.J., H.G., P.Y., and instrument construction were supported by the Materials Science Division of Lawrence Berkeley National Laboratory by the U.S. Department of Energy at Lawrence Berkeley National Lab under Contract No. DE-AC02-05CH11231, "Physical Chemistry of Nanomaterials". J.M.L. is supported as part of the Light Material Interactions in Energy Conversion, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-SC0001293. Daniel J. Hellebusch is thanked for analysis of TEM data.

Keywords

RAY-ABSORPTION SPECTROSCOPY
HEMATITE ALPHA-FE2O3
HARMONIC-GENERATION
STRUCTURAL DYNAMICS
SPECTRA
EDGE
NANOPARTICLES
COMPLEXES
ULTRAFAST
FIELD

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title = "Femtosecond M-2,M-3-Edge Spectroscopy of Transition-Metal Oxides: Photoinduced Oxidation State Change in alpha-Fe2O3",

abstract = "Oxidation-state-specific dynamics at the Fe M-2,M-3-edge are measured on the sub-100 fs time scale using tabletop high-harmonic extreme ultraviolet spectroscopy. Transient absorption spectroscopy of alpha-Fe2O3 thin films after 400 nm excitation reveals distinct changes in the shape and position of the 3p -> valence absorption peak at similar to 57 eV due to a ligand-to-metal charge transfer from 0 to Fe. Semiempirical ligand field multiplet calculations of the spectra of the initial Fe3+ and photoinduced Fe2+ state confirm this assignment and exclude the alternative d-d excitation. The Fe2+ state decays to a long-lived trap state in 240 fs. This work establishes the ability of time-resolved extreme ultraviolet spectroscopy to measure ultrafast charge-transfer processes in condensed-phase systems.",

keywords = "RAY-ABSORPTION SPECTROSCOPY, HEMATITE ALPHA-FE2O3, HARMONIC-GENERATION, STRUCTURAL DYNAMICS, SPECTRA, EDGE, NANOPARTICLES, COMPLEXES, ULTRAFAST, FIELD",

author = "Josh Vura-Weis and Chang-Ming Jiang and Chong Liu and Hanwei Gao and Lucas, {J. Matthew} and {de Groot}, {Frank M. F.} and Peidong Yang and Alivisatos, {A. Paul} and Leone, {Stephen R.}",

year = "2013",

month = nov,

day = "7",

doi = "10.1021/jz401997d",

language = "English",

volume = "4",

pages = "3667--3671",

journal = "Journal of Physical Chemistry Letters",

issn = "1948-7185",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Femtosecond M-2,M-3-Edge Spectroscopy of Transition-Metal Oxides

T2 - Photoinduced Oxidation State Change in alpha-Fe2O3

AU - Vura-Weis, Josh

AU - Jiang, Chang-Ming

AU - Liu, Chong

AU - Gao, Hanwei

AU - Lucas, J. Matthew

AU - de Groot, Frank M. F.

AU - Yang, Peidong

AU - Alivisatos, A. Paul

AU - Leone, Stephen R.

PY - 2013/11/7

Y1 - 2013/11/7

N2 - Oxidation-state-specific dynamics at the Fe M-2,M-3-edge are measured on the sub-100 fs time scale using tabletop high-harmonic extreme ultraviolet spectroscopy. Transient absorption spectroscopy of alpha-Fe2O3 thin films after 400 nm excitation reveals distinct changes in the shape and position of the 3p -> valence absorption peak at similar to 57 eV due to a ligand-to-metal charge transfer from 0 to Fe. Semiempirical ligand field multiplet calculations of the spectra of the initial Fe3+ and photoinduced Fe2+ state confirm this assignment and exclude the alternative d-d excitation. The Fe2+ state decays to a long-lived trap state in 240 fs. This work establishes the ability of time-resolved extreme ultraviolet spectroscopy to measure ultrafast charge-transfer processes in condensed-phase systems.

AB - Oxidation-state-specific dynamics at the Fe M-2,M-3-edge are measured on the sub-100 fs time scale using tabletop high-harmonic extreme ultraviolet spectroscopy. Transient absorption spectroscopy of alpha-Fe2O3 thin films after 400 nm excitation reveals distinct changes in the shape and position of the 3p -> valence absorption peak at similar to 57 eV due to a ligand-to-metal charge transfer from 0 to Fe. Semiempirical ligand field multiplet calculations of the spectra of the initial Fe3+ and photoinduced Fe2+ state confirm this assignment and exclude the alternative d-d excitation. The Fe2+ state decays to a long-lived trap state in 240 fs. This work establishes the ability of time-resolved extreme ultraviolet spectroscopy to measure ultrafast charge-transfer processes in condensed-phase systems.

KW - RAY-ABSORPTION SPECTROSCOPY

KW - HEMATITE ALPHA-FE2O3

KW - HARMONIC-GENERATION

KW - STRUCTURAL DYNAMICS

KW - SPECTRA

KW - EDGE

KW - NANOPARTICLES

KW - COMPLEXES

KW - ULTRAFAST

KW - FIELD

U2 - 10.1021/jz401997d

DO - 10.1021/jz401997d

M3 - Article

SN - 1948-7185

VL - 4

SP - 3667

EP - 3671

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 21

ER -

Femtosecond M-2,M-3-Edge Spectroscopy of Transition-Metal Oxides: Photoinduced Oxidation State Change in alpha-Fe2O3

Abstract

Funding

Keywords

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