Combined static and dynamic intramicellar fluorescence quenching: effects on stationary and time-resolved Stern–Volmer experiments

2019 ◽  
Vol 21 (19) ◽  
pp. 10075-10085 ◽  
Author(s):  
Tim Kohlmann ◽  
Martin Goez
Keyword(s):  
Fluorescence Quenching ◽  
Ground State ◽  
Time Resolved ◽  
Consistent Model

It ain’t necessarily so—existing theories of combined quenching in micelles are flawed. We derive a consistent model, analyze its properties, and apply it to obtain information on ground-state complexes between fluorophore F and quencher Q.

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

scholarly journals Time-Resolved Investigation of the Molecular Chemiluminescence SrI(A2∏1/2,3,2,B2∑+→X2∑+) and the Atomic Resonance Fluorescence Sr(53P1→51S0) Following The Pulsed Dye Laser Generation Of Sr(53PJ) in the Presence of CF3I

1995 ◽  
Vol 16 (2) ◽  
pp. 121-138 ◽  
Author(s):  
S. Antrobus ◽  
D. Husain ◽  
Jie Lei ◽  
F. Castaño ◽  
M. N. Sanchez Rayo
Keyword(s):  
Ground State ◽  
Branching Ratio ◽  
Atomic Emission ◽  
Electronic Energy ◽  
Dye Laser ◽  
Pulsed Dye Laser ◽  
Laser Generation ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Time Resolved

A time-resolved investigation is presented of the electronic energy distribution in SrI following the collision of the optically metastable strontium atom, Sr [5s5p(3PJ)], with the molecule CF3I. Sr[5s5p(3PJ)], 1.807 eV above its 5s2(1S0) electronic ground state, was generated by pulsed dye-laser excitation of ground state strontium vapour to the Sr(53P1) state at , λ =689.3 nm {Sr(53P1←51S0)} at elevated temperature (840 K) in the presence of excess helium buffer gas in which rapid Boltzmann equilibration within the 53PJ spin-orbit manifold takes place. Time resolved atomic emission from Sr(53P1→51S0) at the resonance transition and the molecular chemiluminescence from SrI(A2∏1,2,3/2,B2∑+→X2∑+) resulting from reaction of the excited atom with CF3I were recorded and shown to be exponential in character. SrI in the A2∏1/2,3/2 (172.5, 175.4 kJ mol-1) and B2∑+ (177.3 kJ mol-1) states are energetically accessible on collision by direct-I-atomic abstraction between Sr(3P) and CF3I. The first-order decay coefficients for the atomic and molecular emissions are found to be equal under identical conditions and hence SrI(A2∏1/2,3/2, B2∑+) are shown to arise from direct I- atom abstraction reactions. The molecular systems recorded were SrI (A2∏1/2→X2∑+, Δv=0, λ=694 nm), SrI(A2∏3/2→X2∑+, Δv=0, λ=677 nm) and SrI(B2∑+→X2∑+) (Δv=0, λ=674 nm), dominated by the Δv=0 sequences on account of Franck-Condon considerations. The combination of integrated m61ecular and atomic intensity measurements yields estimates of the branching ratios into the specific electronic states, A1/2, A3/2 and B, arising from Sr(53PJ)+CF3I which are found to be as follows: A1/2,1.2 × 10-2; A3/2, 6.7 × 10-3; B, 5.1 × 10-3 yielding ∑SrI(A1/2+A3/2+B)=2.4 × 10-2. As only the X, A and B states SrI are accessible on reaction, assuming that the removal of Sr(53PJ) occurs totally by chemical removal, this yields an upper limit for the branching ratio into the ground state of ca. 98%. The present results are compared with previous time-resolved measurements on excited states of strontium halides that we have reported on various halogenated species resulting from reactions of Sr(53PJ), together with analogous chemiluminescence studies on Sr(3PJ) and Ca(43PJ) from molecular beam measurements.

Size, Hydration, and Shape of SDS/Heptane Micelles Investigated by Time-Resolved Fluorescence Quenching and Electron Spin Resonance

Langmuir ◽  
2001 ◽  
Vol 17 (22) ◽  
pp. 6765-6770 ◽  
Author(s):  
Radha Ranganathan ◽  
Miroslav Peric ◽  
Rosa Medina ◽  
Ulises Garcia ◽  
Barney L. Bales ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Fluorescence Quenching ◽  
Electron Spin ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Spin Resonance

scholarly journals Fluorescent chemosensors for metal ions based on 3-(2-benzoxazol-5-yl)alanine skeleton

2010 ◽  
Vol 8 (3) ◽  
pp. 674-686 ◽  
Author(s):  
Magda Milewska ◽  
Katarzyna Guzow ◽  
Wiesław Wiczk
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Metal Ions ◽  
Ground State ◽  
Transition Metal Ions ◽  
Fluorescent Chemosensors ◽  
Time Resolved Fluorescence ◽  
Absorption Bands ◽  
Time Resolved ◽  
Ratiometric Sensors

AbstractThe ability of new chelate ligands, benzoxazol-5-yl-alanine derivatives substituted in position 2 by heteroaromatic substituent, to form complexes with selected metal ions in acetonitrile are studied by means of absorption and steady-state and time-resolved fluorescence spectroscopy. Among the ligands studied, only azaaromatic derivatives form stable complexes with transition metal ions in the ground state. Their absorption bands are bathochromically shifted enabling to use those ligands as ratiometric sensors. The fluorescence of each ligand is quenched by metal ions, however, in the presence of Cd(II) and Zn(II) ions a new red shifted emission band is observed.

Aggregation Numbers of Cationic Oligomeric Surfactants:  A Time-Resolved Fluorescence Quenching Study

Langmuir ◽  
2006 ◽  
Vol 22 (6) ◽  
pp. 2551-2557 ◽  
Author(s):  
Laurent Wattebled ◽  
André Laschewsky ◽  
Alain Moussa ◽  
Jean-Louis Habib-Jiwan
Keyword(s):  
Fluorescence Quenching ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Aggregation Numbers

scholarly journals Structural dynamics of the Ca2+-ATPase studied by time-resolved infrared spectroscopy

2008 ◽  
Vol 22 (2-3) ◽  
pp. 63-82 ◽  
Author(s):  
Andreas Barth
Keyword(s):  
Infrared Spectroscopy ◽  
Structural Dynamics ◽  
Ground State ◽  
Transfer Reaction ◽  
High Reactivity ◽  
Acetyl Phosphate ◽  
Time Resolved ◽  
Closed Conformation ◽  
Sarcoplasmic Reticulum Membrane ◽  
Time Resolved Infrared Spectroscopy

This review discusses the contribution of time-resolved infrared spectroscopy to the understanding of the Ca2+pump in the sarcoplasmic reticulum membrane of skeletal muscle cells (SERCA1a). The focus is on interactions of the substrate ATP with the ATPase and on the bond parameters of the phosphoenzyme phosphate group. Functional groups throughout the ATP molecule are important for stabilising the closed conformation of the ATP–ATPase complex and for fast phosphorylation of the ATPase. Dissociation of the reaction product ADP after phosphorylation leads to a more open average conformation of the enzyme and does not trigger the transition from the first phosphoenzyme Ca2E1P to the second E2P. The P–O bond between phosphate and aspartyl moieties is weaker in Ca2E1P and E2P than in acetyl phosphate in aqueous solution, which explains the high reactivity of the phosphoenzymes. This ground state property of the phosphoenzymes prepares for a phosphate transfer reaction with dissociative character.

scholarly journals Спиновая динамика отрицательно заряженных экситонов в квантовых точках InP/(In,Ga)P в магнитном поле

2020 ◽  
Vol 62 (11) ◽  
pp. 1816
Author(s):  
С.В. Некрасов ◽  
Ю.Г. Кусраев ◽  
И.А. Акимов ◽  
L. Langer ◽  
M. Kotur ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Circular Polarization ◽  
Ground State ◽  
Heavy Hole ◽  
Spin Dynamics ◽  
Nuclear Spins ◽  
Time Resolved ◽  
Exciton Ground State ◽  
Charged Exciton

The dynamics of the photoluminescence negative circular polarization of the InP/(In,Ga)P quantum dots ensemble was studied. We find that in the time-resolved dependences of the polarization there are no oscillations in Voigt magnetic field. Also, with increasing field the polarization declines to zero. Such behavior is attributed to the peculiarities of the negatively charged exciton spin dynamics, particularly, to the fact that in the negatively charged exciton ground state the spin dynamics is governed by the heavy hole. We show that magnetic field depolarization of the photoluminescence occurs once the field of dynamically polarized nuclear spins acting on electron spins is surpassed.

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