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Femtosecond Transient Infrared Spectroscopy
Project Description:
Ultrashort laser pulses are used to observe fast molecular, electronic and
chemical reaction processes which occur in the condensed phase. We have
developed unique femtosecond mid-infrared spectroscopic techniques to study
highly excited molecular vibrational states, vibrational energy transfer,
photochemical reactions, and the dynamics of hydrogen bond formation and
rupture. These measurements help identify new transient species and determine
energy transfer rates, which serve to improve models of condensed phase
chemistry. Current directions include measurements of isomerization processes
on model biological species, organometallic photo-switches and polymerization
reactions. We are also developing sources of ultrafast pulses in the terahertz
frequency region to be used to directly probe electron and phonon dynamics and
related optical properties of semiconductors, organic conducting thin films,
quantum well structures and optical materials (see:
Ultrafast Terahertz
Spectroscopy and Imaging).
Resources:
Three independent femtosecond laser systems used for generating ultrafast
pulses in the far IR (THz) through the UV; infrared and visible multi-element
focal plane array cameras and instrumentation for capturing the transient
spectra of samples with a single laser pulse; detection systems capable of
making accurate time-resolved amplitude and phase measurements on THz pulses as
they interact with samples; crystals for nonlinear frequency conversion.
Pulsed dye-laser based system with diode-pumped solid-state Nd:Vanadate,
2 Watt, 80 MHz pump for three independently tunable synchronous dye
lasers. Home-built seeded 20 Hz Nd:YAG regenerative amplifier generating
30 mJ 532 nm pulses to pump three linear dye amplifier chains (ca.
0.7 mJ pulse energy).
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Transient infrared (points) and final FTIR product (solid line) spectra of
after photolyzing a RCpMn(CO)3 “molecular switch” species
(R=two sulfur containing pendant groups) showing that an initial distribution
of product and transient n-heptane solvate is formed.
From J. Yeston et al. |
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Mid-infrared pump-probe apparatus including dual-beam probe
normalization to reduce spectral intensity fluctuations and IR spectrograph
outfitted with a cooled 256×256 InSb Focal Plane Array camera as the detector.
References:
"Time-Resolved Infrared Absorption Study of Cyclopentadienyl Manganese
Tricarbonyl Derivatives: Chelation with Pendant Sulfides in Acetonitrile,"
T.T. To, T.J. Burkey, and E.J. Heilweil,
J. Phys. Chem., (submitted December 15, 2005).
"Ultrafast Chelation Dynamics of Cyclopentadienyl Manganese Tricarbonyl
Derivatives with Pendant Sulfides,"
J.S. Yeston, T.T. To, T.J. Burkey, and E.J. Heilweil,
J. Phys. Chem. B Lett. 108, 4582-4585 (2004).
"Femtosecond Infrared Coherent Excitation of Liquid Phase Vibrational Population
Distributions (v>5),"
T. Witte, J.S. Yeston, M. Motzkus, E.J. Heilweil, and K-L. Kompa,
Chem. Phys. Lett. 392, 156-161, (2004).
"Applications of Ultrafast Transient Infrared Spectroscopies,"
T. Heimer and E. Heilweil,
TRVS X Proc. Special Issue J. Chem. Soc. Japan. ed. by H. Hamaguchi,
75(5), 899-908 (2002).
"Vibrational Population Control in Liquid - Phase Metal Carbonyls,"
V.D. Kleiman, J.S. Melinger, and E.J. Heilweil,
Proc. of Femtochemistry and Femtobiology V Conf., Toledo Spain, ed. by
Abderrazzak Douhal and Jesus Santamaria,
Femtochemistry and Femtobiology: Ultrafast Dynamics in Molecular Science,
(World Scientific Publishing Co. Pte. Ltd., Singapore, 2002), pp. 409,
ISBN: 981-02-4866-0.
"Applications of Broadband Transient Infrared Spectroscopy,"
E.J. Heilweil,
book chapter in Ultrafast Infrared and Raman Spectroscopy, ed. by
M.D. Fayer (Marcell-Dekker, NY, 2000).
"Electron Injection, Recombination and Halide Oxidation Dynamics
at Dye-sensitized Metal Oxide Interfaces,"
T.A. Heimer, E.J. Heilweil, C.A. Bignozzi, and G.J. Meyer,
J. Phys. Chem. B TRVS IX, Special Issue 104, 4256 (2000).
"Ultrafast Ring Closure Energetics and Dynamics of Cyclopentadienyl
Manganese Tricarbonyl Derivatives,"
T. Jiao, Z. Pang, T.J. Burkey, R.F. Johnston, T.A. Heimer, V.D. Kleiman,
and E.J. Heilweil,
J. Am. Chem. Soc. 121, 4618 (1999).
(Preprint 91 k)
"Controlling Condensed-phase Vibrational Excitation with Tailored Infrared
Pulses," Special issue on "Coherence in Chemical Dynamics,"
V.D. Kleiman, S.M. Arrivo, J.S. Melinger and E.J. Heilweil,
Chem. Phys. 233, 207 (1998). (Preprint
151 k)
"Broadband Femtosecond Transient Infrared Spectroscopy using a
256×256 InSb Focal-Plane Detector,"
S.M. Arrivo, V.D. Kleiman, T.P. Dougherty and E.J. Heilweil ,
Opt. Lett. 22(19), 1488 (1997).
"Direct Time-resolved Infrared Measurement of Electron Injection
in Dye-Sensitized Titanium Dioxide Films,"
T A. Heimer and E.J. Heilweil,
J. Phys. Chem. B 51, 10990 (1997).
"Conservation of Vibrational Excitation During Hydrogen Bonding
Reactions,"
S.M. Arrivo and E.J. Heilweil,
J.Phys. Chem. 100(29), 11975 (1996).
"Bimolecular Interactions in (Et)3SiOH:Base:CCl4
Hydrogen-Bonded Solutions studied by Deactivation of the "Free"
OH-Stretch Vibration,"
W.T. Grubbs, T.P. Dougherty, and E.J. Heilweil,
J. Am. Chem. Soc. 117, 11989 (1995).
"Ultrafast Infrared Spectroscopy of Vibrational CO-Stretch Up-Pumping
and Relaxation Dynamics in Metal Hexacarbonyls,"
S.M. Arrivo, T.P. Dougherty, W.T. Grubbs and E.J. Heilweil,
Chem. Phys. Lett. 235, 247 (1995).
"Ultrafast Transient Infrared Absorption Studies of M(CO)6
(M=Cr, Mo, W) Photoproducts in n-Hexane Solution,"
T.P. Dougherty and E.J. Heilweil,
Chem. Phys. Lett. 227, 19-25 (1994).
"Picosecond Time-Resolved Adsorbate Response to Substrate Heating:
Spectroscopy and Dynamics of CO/Cu(100),"
T.A. Germer, J.C. Stephenson, E.J. Heilweil, and R.R. Cavanagh,
J. Chem. Phys. 101, 1704 (1994).
"A Dual Beam Sub-picosecond Broadband Infrared Spectrometer,"
T.P. Dougherty and E.J. Heilweil,
Opt. Lett. 19, 129 (1994).
"Ultrafast Infrared Response of Adsorbates on Metal Surfaces:
Vibrational Lifetime of CO/Pt(111),"
J.D. Beckerle, M.P. Casassa, R.R. Cavanagh, E.J. Heilweil, and J.C. Stephenson,
Phys. Rev. Lett. 64, 2090 (1990).
"Picosecond Studies of Vibrational Energy Transfer in Surface
Adsorbates,"
E.J. Heilweil, M.P. Casassa, R.R. Cavanagh, and J.C. Stephenson,
Ann. Rev. Phys. Chem. 40, 143 (1989).
"Picosecond Study of the Population Lifetime of CO(v=1) on
SiO2-supported Rhodium Particles,"
E.J. Heilweil, R.R. Cavanagh, and J.C. Stephenson,
J. Chem. Phys. 89, 5342 (1988).
"Population Relaxation of CO(v=1) Vibrations in Solution Phase
Metal-Carbonyl Complexes,"
E.J. Heilweil, R.R. Cavanagh, and J.C. Stephenson,
Chem. Phys. Lett. 134, 181 (1987).
"Population Lifetimes of OH(v=1) and OD(v=1) Stretching Vibrations of
Alcohols and Silanols in Dilute Solution,"
E.J. Heilweil, M.P. Casassa, R.R. Cavanagh, and J.C. Stephenson,
J. Chem. Phys. 85, 5004 (1986).
"Temperature Dependence of the Vibrational Population Lifetime
of OH(v=1) in Fused Silica,"
E.J. Heilweil, M.P. Casassa, R.R. Cavanagh, and J.C. Stephenson,
Chem. Phys. Lett. 117, 185 (1985).
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