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Transient Absorption

Transient Absorption / Laser Flash Photolysis is a technique for studying transient absorption of chemical and biological species generated by a short intense light pulse from a pulsed laser source (‘pump source’).

This intense light pulse creates short lived photo-excited intermediates such as excited states, radicals and ions. All these intermediates are generated in concentrations large enough for chemical and physical interaction to occur and for direct observation of the associated temporally changing absorption characteristics. These absorption changes are recorded using a spectrally continuous Xenon lamp (‘probe source’) forming the background in a single beam absorption spectrometer. The probe source is operated in a pulsed mode to enhance the photon flux for measurements in short time ranges.

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Description

Transient Absorption: flash photolysis kineticThe sample being investigated is exposed to an intense laser pump pulse, which creates the transient species, and the probe source, which forms the background for the time dependant absorption measurement. For time scales in the microsecond and nanosecond range the required high background level of the probe light is created by the intense flash from the pulsed xenon lamp which – after some stabilisation period – reaches a sufficiently flat plateau.

This plateau level represents the pre-photolysis background level of the transmitted light through the sample. At a pre-set time after lamp triggering, when the pulse plateau is flat, the excitation laser is triggered creating the transient species under investigation. The absorption of the transient species is usually time dependent and produces a time dependent change in the transmission of the sample.

The change in optical density, ΔOD, can then be analysed using exponential least squares fitting algorithms, resulting in transient lifetimes or rate constants.

To protect the sample against photobleaching by unnecessary radiation exposure between measurements and as a means to control background measurements, high speed shutters are operated to control the probe and laser beam prior to entering the sample. For laser induced emission measurements the probe shutter remains permanently closed.

Products

Applications

Transient absorption measurements / laser flash photolysis is applicable to liquid, gaseous, and solid samples.

Liquids are usually measured in a cuvette with the pump beam and the probe beam overlapping orthogonally (transverse excitation). In gaseous samples the concentration of the participating molecules is much lower and a co-linear setup between the pump and probe beam is preferred to improve the signal to noise ratio. Film samples, powders and non transparent bulk samples are generally studied in a diffuse reflectance setup.

  • Transient Absorption and Photobleaching
  • Triplet-Triplet Annihilation
  • Oxygen Quenching of Transient Absorption Decays
  • Spectrally Dependent Transient Kinetics

 

Publications

AuthorYearTitleJournalAdditional detailsVolumePagesInstrumentsPublication details
Cédric Mongin et al.2016Direct observation of triplet energy transfer from semiconductor nanocrystalsScience
Volume:351
Pages:369-372
Year:2016
Author:Cédric Mongin et al.
Journal:Science
Volume:351
Pages:369-372
Year:2016
Instruments
351369-372Direct observation of triplet energy transfer from semiconductor nanocrystals
Author:Cédric Mongin et al.Further info
Zongle Li et al.2016An Ethylenediamine-Modified Graphene Oxide Covalently Functionalized with Tetracarboxylic Zn(II) Phthalocyanine Hybrid for Enhanced Nonlinear Optical PropertiesPhotochemical & Photobiological Sciences
Volume:15
Pages:910-919
Year:2016
Author:Zongle Li et al.
Journal:Photochemical & Photobiological Sciences
Volume:15
Pages:910-919
Year:2016
Instruments
15910-919An Ethylenediamine-Modified Graphene Oxide Covalently Functionalized with Tetracarboxylic Zn(II) Phthalocyanine Hybrid for Enhanced Nonlinear Optical Properties
Author:Zongle Li et al.Further info
Journal:Photochemical & Photobiological Sciences
Volume:15
Pages:910-919
Year:2016

Instruments

Leila Alibabaeia, et al.2013Solar water splitting in a molecular photoelectrochemical cellPNAS
Volume:110
Pages:20008-20013
Year:2013
Author:Leila Alibabaeia, et al.
Journal:PNAS
Volume:110
Pages:20008-20013
Year:2013
Instruments
11020008-20013Solar water splitting in a molecular photoelectrochemical cell
Author:Leila Alibabaeia, et al.Further info
Journal:PNAS
Volume:110
Pages:20008-20013
Year:2013

Instruments

Jamie C. Wang et al.2015Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled BilayersThe Journal of Physical Chemistry C
Volume:119(7)
Pages:3502-3508
Year:2015
Author:Jamie C. Wang et al.
Journal:The Journal of Physical Chemistry C
Volume:119(7)
Pages:3502-3508
Year:2015
Instruments
119(7)3502-3508Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers
Author:Jamie C. Wang et al.Further info
Journal:The Journal of Physical Chemistry C
Volume:119(7)
Pages:3502-3508
Year:2015

Instruments

Dariusz M. Niedzwiedzki et al.2014Excited state properties of chlorophyll f in organic solvents at ambient and cryogenic temperaturesPhotosynthesis Research
Volume:121
Pages:25-34
Year:2014
Author:Dariusz M. Niedzwiedzki et al.
Journal:Photosynthesis Research
Volume:121
Pages:25-34
Year:2014
Instruments
12125-34Excited state properties of chlorophyll f in organic solvents at ambient and cryogenic temperatures
Author:Dariusz M. Niedzwiedzki et al.Further info
Journal:Photosynthesis Research
Volume:121
Pages:25-34
Year:2014

Instruments

Lesley Tilleman, et al.2015A Globin Domain in a Neuronal Transmembrane Receptor of Caenorhabditis elegans and Ascaris suum: Molecular Modeling and Functional PropertiesThe Journal of Biological Chemistry
Volume:290
Pages:10336-10352
Year:2015
Author:Lesley Tilleman, et al.
Journal:The Journal of Biological Chemistry
Volume:290
Pages:10336-10352
Year:2015
Instruments
29010336-10352A Globin Domain in a Neuronal Transmembrane Receptor of Caenorhabditis elegans and Ascaris suum: Molecular Modeling and Functional Properties
Author:Lesley Tilleman, et al.Further info
Journal:The Journal of Biological Chemistry
Volume:290
Pages:10336-10352
Year:2015

Instruments

Documents

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