Comprehensive data analysis of femtosecond transient absorption spectra: A review

Ruckebusch, Cyril; Sliwa, Michel; Pernot, Pascal; Juan, Anna de; Tauler, Romà

doi:10.1016/j.jphotochemrev.2011.10.002

Cited by 315 publications

(291 citation statements)

References 150 publications

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“…It is worth noticing that TA signal is typically given by the sum of several, different terms: excited state absorption (ΔA > 0), ground state bleaching (ΔA < 0), stimulated emission (ΔA < 0), and photoluminescence (ΔA < 0). 64 Under our experimental conditions, we do expect that neither stimulated emission nor ground state bleaching play any significant role. However, a small negative contribution to ΔA coming from photoluminescence of TiO 2 nanocrystals is likely to occur when exciting at 300 nm, because of the strong optical absorption of anatase in the near-UV range.…”

Section: ■ Results and Discussionmentioning

confidence: 75%

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent

et al. 2014

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The relaxation dynamics of charge carriers of organic capped TiO2 nanorods dispersed in chloroform was investigated by femtosecond transient absorption in a weak-excitation regime. Anisotropic TiO2 nanocrystals were excited in the UVvis range, using different pump wavelengths, namely above (300 nm), close to (350 nm), and below (430 nm) the direct band gap of anatase TiO2. We show that the ultrafast dynamics strongly depends on excitation wavelength and determine the time constants of all the processes entering the relaxation. Moreover, we demonstrate that two transient absorption bands at 500 and 700 nm, typically attributed to trapped h(+) and e, respectively, are accessible only when TiO2 is photoexcited well above the band gap, while there is no evidence of such bands when TiO2 is photoexcited close to or below its band gap. In such cases the observed dynamics are attributed to trapped excitons

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Section: ■ Results and Discussionmentioning

confidence: 75%

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent

et al. 2014

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“…It is to be noted that a prior understanding of the excited‐state dynamics involved in these proteins should be available. Otherwise the global analysis could mislead if the underlying dynamics are more complex than the assumption …”

Section: Resultsmentioning

confidence: 99%

Ultrafast Heme Dynamics of Ferric Cytochrome c in Different Environments: Electronic, Vibrational, and Conformational Relaxation

Karunakaran

2015

ChemPhysChem

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The excited-state dynamics of ferric cytochrome c (Cyt c), an important electron-transfer heme protein, in acidic to alkaline medium and in its unfolded form are investigated by using femtosecond pump-probe spectroscopy, exciting the heme and Tryptophan (Trp) to understand the electronic, vibrational, and conformational relaxation of the heme. At 390 nm excitation, the electronic relaxation of heme is found to be ≈150 fs at different pH values, increasing to 480 fs in the unfolded form. Multistep vibrational relaxation dynamics of the heme, including fast and slow processes, are observed at pH 7. However, in the unfolded form and at pH 2 and 11, fast phases of vibrational relaxation dominate, revealing the energy dissipation occurring through the covalent bond interaction between the heme and the nearest amino acids. A significant shortening of the excited-state lifetime of Trp is observed at various pH values at 280 nm excitation due to resonance energy transfer to the heme. The longer time constant (25 ps) observed in the unfolded form is attributed to a complete global conformational relaxation of Cyt c.

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“…We have applied a Principal Component Analysis to this linear problem 19,38 using the data analysis environment Igor Pro from Wavemetrics. 39 The decays are considered as vectors in a space of 4096 dimensions.…”

Section: Data Treatmentmentioning

confidence: 99%

Quenching Dynamics in CdSe Nanoparticles: Surface-Induced Defects upon Dilution.

et al. 2012

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We have analyzed the decays of the fluorescence of colloidal CdSe quantum dots (QDs) suspensions during dilution and titration by the ligands. A ligand shell made of a combination of trioctylphosphine (TOP), oleylamine (OA), and stearic acid (SA) stabilizes the assynthesized QDs. The composition of the shell was analyzed and quantified using high resolution liquid state 1H nuclear magnetic resonance (NMR) spectroscopy. A quenching of the fluorescence of the QDs is observed upon removal of the ligands by diluting the stock solution of the QDs. The fluorescence is restored by the addition of TOP. We analyze the results by assuming a binomial distribution of quenchers among the QDs and predict a linear trend in the time-resolved fluorescence decays.We have used a nonparametric analysis to show that for our QDs, 3.0 ( 0.1 quenching sites per QD on average are revealed by the removal of TOP. We moreover show that the quenching rates of the quenching sites add up. The decay per quenching site can be compared with the decay at saturation of the dilution effect. This provides a value of 2.88 ( 0.02 for the number of quenchers per QD. We extract the quenching dynamics of one site. It appears to be a process with a distribution of rates that does not involve the ligands.

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Comprehensive data analysis of femtosecond transient absorption spectra: A review

Cited by 315 publications

References 150 publications

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent

Ultrafast Heme Dynamics of Ferric Cytochrome c in Different Environments: Electronic, Vibrational, and Conformational Relaxation

Quenching Dynamics in CdSe Nanoparticles: Surface-Induced Defects upon Dilution.

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Comprehensive data analysis of femtosecond transient absorption spectra: A review

Cited by 315 publications

References 150 publications

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO2 Nanorods in Organic Solvent

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO2 Nanorods in Organic Solvent

Ultrafast Heme Dynamics of Ferric Cytochrome c in Different Environments: Electronic, Vibrational, and Conformational Relaxation

Quenching Dynamics in CdSe Nanoparticles: Surface-Induced Defects upon Dilution.

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Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent

Excitation-Dependent Ultrafast Carrier Dynamics of Colloidal TiO₂ Nanorods in Organic Solvent