Ultrafast dynamics of malachite green at the air/water interface studied by femtosecond time-resolved electronic sum frequency generation (TR-ESFG): an indicator for local viscosity

Sen, Pratik; Yamaguchi, S.; Tahara, Tahei

doi:10.1039/b908097j

Cited by 42 publications

(67 citation statements)

References 47 publications

(85 reference statements)

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“…3(b). A pump-probe cross correlation of 35 fs in the NIR and slightly longer in the UV is reached and matches the resolution of previous one- 14,20 or two-colour pump-probe 15 and uorescence up-conversion 18 measurements. The strongest feature in the transient spectrum is the region of negative optical density around 635 nm (blue colours; Fig.…”

Section: Selection Of Sample Molecules and Processessupporting

confidence: 61%

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

et al. 2013

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Complex multi-stage relaxation and reaction pathways after the optical excitation of molecules makes the disentanglement of the underlying mechanisms challenging. We present four examples that a new transient spectrometer with excitation fully tunable from the deep UV to the IR and 225 to 1700 nm probing allows for an analysis with greatly reduced ambiguity. The temporal resolution of about 50 fs allows us to resolve all relevant processes. For each example there is a new twist in the sequence of relaxation steps that had previously been overlooked. In malachite green it appears that the importance of the phenyl twisting has been overemphasized and rather a charge transfer state should be considered. In TINUVIN-P the predicted twisting as the driving motion for the ultrafast IC is confirmed and leads to a resolution of the earlier puzzle that the sub-5 ps regime shows kinetics deviating from a pure cooling process despite the sub-ps proton transfer cycle. For the bond cleavage of Ph 2 CH-Cl and Ph 2 CH-Br the degree of electron transfer within the radical pair can now be determined quantitatively and leads to a profound understanding of the long term cation yield. For the first time coherent wavepacket motion in the photoproducts is reported. Last but not least the measurement of the GSB recovery in the deep UV allows for the surprising result, that even after S 2 excitation of cyclopentenones the triplet states are reached with near unity probability within a few picoseconds.

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Section: Selection Of Sample Molecules and Processessupporting

confidence: 61%

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

et al. 2013

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“…The solid line in Figure 5 is the average of 10 successive measurements (∼1 h), demonstrating the ability in acquiring high quality data in relatively quick time. Comparing our data with that measured by Sen et al 39 using the conventional SHG (proportional to | χ (2) | 2 ) reveals very similar dynamics and timescales when the square-root of their raw data is considered. In terms of signal to noise, our single run data-set (which contains about twice as many datapoints over the first 30 ps) is of comparable quality as that presented by Sen et al…”

Section: Resultsmentioning

confidence: 54%

“…Additionally, it has optical transitions (S 1 ← S 0 and S 2 ← S 0 at 610 and 400 nm, respectively) that are readily accessible for resonant enhancement and provides a strong SHG (and SFG) signal. 38,39 All reported experiments used a 10 µM solution of MG in water.…”

Section: Resultsmentioning

confidence: 99%

Time-resolved phase-sensitive second harmonic generation spectroscopy

Nowakowski

Woods

Bain

et al. 2015

The Journal of Chemical Physics

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. A methodology based on time-resolved, phase-sensitive second harmonic generation (SHG) for probing the excited state dynamics of species at interfaces is presented. It is based on an interference measurement between the SHG from the sample and a local oscillator generated at a reference together with a lock-in measurement to remove the large constant offset from the interference. The technique is characterized by measuring the phase and excited state dynamics of the dye malachite green at the water/air interface. The key attributes of the technique are that the observed signal is directly proportional to sample concentration, in contrast to the quadratic dependence from non-phase sensitive SHG, and that the real and imaginary parts of the 2nd order non-linear susceptibility can be determined independently. We show that the method is highly sensitive and can provide high quality excited state dynamics in short data acquisition times. C 2015 AIP Publishing LLC.[http://dx

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“…1,2 Recent interest in these dyes has focused on the environmental sensitivity of their optical response. [3][4][5][6][7][8][9][10][11] In particular, a common binding-dependent fluorescence enhancement makes these dyes useful biological markers. [4][5][6]12 The fluorescence enhancement is attributed to the suppression of a competing double-bond isomerization reaction, the rate of which is influenced by the local viscosity.…”

Section: Introductionmentioning

confidence: 99%

A three-state effective Hamiltonian for symmetric cationic diarylmethanes

Olsen

McKenzie

2012

The Journal of Chemical Physics

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Comparison of density functionals for energy and structural differences between the high-[ 5 T 2g :(t 2g ) 4 (e g ) 2 ] and low-[ 1 A 1g :(t 2g ) 6 (e g ) 0 ] spin states of iron (II) We analyze the low-energy electronic structure of a series of symmetric cationic diarylmethanes, which are bridge-substituted derivatives of Michler's Hydrol Blue. We use a four-electron, threeorbital complete active space self-consistent field and multi-state multi-reference perturbation theory model to calculate a three-state diabatic effective Hamiltonian for each dye in the series. We exploit an isolobal analogy between the active spaces of the self-consistent field solutions for each dye to represent the electronic structure in a set of analogous diabatic states. The diabatic states can be identified with the bonding structures in classical resonance-theoretic models of cyanine dyes. We identify diabatic states with opposing charge and bond-order localization, analogous to the classical resonance structures, and a third state with charge on the bridge. While the left-and right-charged structures are similar for all dyes, the structure of the bridge-charged diabatic state, and the Hamiltonian matrix elements connected to it, change significantly across the series. The change is correlated with an inversion of the sign of the charge carrier on the bridge, which changes from an electron pair to a hole as the series is traversed.

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Ultrafast dynamics of malachite green at the air/water interface studied by femtosecond time-resolved electronic sum frequency generation (TR-ESFG): an indicator for local viscosity

Abstract: Interplay of theory and computation in chemistryexamples from on-water organic catalysis, enzyme catalysis, and single-molecule fluctuations

Cited by 42 publications

References 47 publications

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

Time-resolved phase-sensitive second harmonic generation spectroscopy

A three-state effective Hamiltonian for symmetric cationic diarylmethanes

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