Fluorescence Lifetime and Quenching Rates for N,N,N′,N′-Tetramethyl-P-Phenylenediamine in the Vapor Phase

1989 ◽  
Vol 43 (8) ◽  
pp. 1406-1409 ◽  
Author(s):  
S. K. Nickle ◽  
L. A. Melton
Keyword(s):  
Vapor Phase ◽  
Fluorescence Lifetime ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Rate ◽  
Electronically Excited ◽  
Visualization Systems ◽  
Fuel Evaporation ◽  
Vapor Liquid

The fluorescence lifetime of N,N,N′,N′-tetramethyl- p-phenyIenediamine (TMPD) in the vapor phase has been determined to be 3.2 ± 0.3 ns for excitation at 337 nm. The rate constants for quenching of electronically excited TMPD by ground-state TMPD, O2, and CO2 have been determined to be <1 × 10−10 cm3/s, (9.9 ± 1.0) × 10−10 cm3/s, and <4 × 10−13 cm3/s, respectively. The rate for TMPD implies that self-quenching is negligible up to pressures of at least 10 Torr. The quenching rate by oxygen is sufficiently high to ensure that use of TMPD as a quantitative marker for fuel evaporation in exciplex-based vapor/liquid visualization systems is probably not possible if significant quantities of oxygen—as would be the case in combustion environments—are present.

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 Measurements of rate constants of O2(b) quenching by CH4, NO, N2O at temperatures 300-800 K

2018 ◽  
Vol 209 ◽  
pp. 00006
Author(s):  
G.I. Tolstov ◽  
M.V. Zagidullin ◽  
N.A. Khvatov ◽  
I.A. Medvedkov ◽  
A.M. Mebel ◽  
...  
Keyword(s):  
Rate Constants ◽  
Room Temperature ◽  
Quenching Rate ◽  
Important Place ◽  
The Past ◽  
Tunable Dye Laser ◽  
Deactivation Kinetics ◽  
Electronically Excited ◽  
Excited Oxygen ◽  
Good Agreement

Electronically excited oxygen has an important place in the kinetic schemes of the processes taking place in the atmosphere, in the active medium of an oxygen-iodine laser, and in plasma-assisted combustion1. Over the past decades, a large amount of data on the rate constants of quenching O2(b) on a large number of collision partners has been accumulated. However, they mostly refer to the results of measurements at room temperature. In this paper, rate constants for the quenching of O2(b) by collisions with N2O, NO, and CH4 have been determined in the temperature range from 297 to 800 K, by the laser-induced fluorescence method. O2(b) was excited by pulses from a tunable dye laser, and the deactivation kinetics were followed via observing the temporal behavior of the b1Σg+→ X3Σg- fluorescence. From the analysis of experimental results, the following temperature dependencies of the quenching rate constants by these gases were obtained, and could be represented by the expressions: kNO=(1.77±0.2)×10-24×T3.5 exp(1138±37/T); kN2O=(2.63±0.14)×10-16×T1.5×exp(590±26/T) and kCH4=(3.54±0.4)×10-18×T1.5×exp(-220±24/T) cm3s-1. All of the rate constants measured at room temperature were found to be in good agreement with previously reported values.

Quenching of Fluorescence of Chloropentafluoroacetone by Saturated Hydrocarbons

1972 ◽  
Vol 50 (9) ◽  
pp. 1429-1432 ◽  
Author(s):  
A. J. Yarwood
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Singlet State ◽  
Fluorescence Yield ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Quenching Rate ◽  
Saturated Hydrocarbons ◽  
Phase Measurements ◽  
Electronically Excited

Saturated hydrocarbons can quench the electronically excited singlet state of a simple ketone in the gas phase. Measurements on the quenching of the fluorescence yield of chloropentafluoroacetone at 23 °C show that different saturated hydrocarbons can deactivate the excited singlet state with varying efficiencies. The quenching rate constants are reported and possible relationships considered.

Determination of the Fluorescence Lifetime and Oxygen Quenching Rate of Vapor-Phase Fluoranthene at High Oxygen Pressures

1994 ◽  
Vol 48 (8) ◽  
pp. 969-972 ◽  
Author(s):  
Michael Haug ◽  
Hans-Joachim Schulpin
Keyword(s):  
Emission Spectrum ◽  
Vapor Phase ◽  
Fluorescence Lifetime ◽  
Oxygen Pressure ◽  
High Oxygen ◽  
Excitation Wavelength ◽  
Oxygen Quenching ◽  
Quenching Rate

The fluorescence lifetime and oxygen quenching rate for vapor-phase fluoranthene are reported for oxygen pressures up to 5.2 bar and temperatures up to 553 K. The unquenched lifetime is found to be 27 ns at an excitation wavelength of 308 nm. Furthermore, the emission spectrum is shown to be dependent on the oxygen pressure.

Measurement of the Natural Lifetimes and Quenching Rate Constants of OH(2Σ+, v = 0,1) and OD(2Σ+, v = 0,1) Radicals

1973 ◽  
Vol 28 (2) ◽  
pp. 249-256 ◽  
Author(s):  
K. H. Becker ◽  
D. Haaks
Keyword(s):  
Rate Constants ◽  
Fluorescence Decay ◽  
Quenching Rate ◽  
Pulse Photolysis ◽  
Electronic Interactions ◽  
Electronically Excited ◽  
Vacuum Uv

The lifetimes of OH(2Σ+) and OD(2Σ+) radicals were measured by using pulse-photolysis of water and methanol in the vacuum-uv for the production of the electronically excited radicals. From the fluorescence decay measurements the natural lifetimes, as well as the quenching rate constants for several added gases such as H2O, CH3OH, H2, N2, Ar, and He were determined. In particular, the natural lifetime of OH (2Σ+, v = 0), τ = (1.00 ± 0.06) · 10-6 s, was corrected for rotation-vibration as well as for rotation-electronic interactions resulting in a lifetime of (0.83 ± 0.08) · 10-6 s for the rotationless state. A lifetime of (0.82 ± 0.08) · 10-6 s was derived for the rotationless state of OD(2Σ+,v = 0).

Quenching of the singlet and triplet state of benzene by halogenated alkanes in the vapor phase

1982 ◽  
Vol 60 (13) ◽  
pp. 1767-1774 ◽  
Author(s):  
H. A. Khwaja ◽  
G. P. Semeluk ◽  
I. Unger
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Vapor Phase ◽  
Linear Dependence ◽  
Rate Constants ◽  
Singlet State ◽  
Quenching Rate ◽  
Order Of Magnitude ◽  
Halogenated Alkanes ◽  
Klein’S Model

The second order rate constants (kq) for the quenching of the singlet state of benzene by several halogenated alkanes (viz. CH2Br2, CCl4, CH3CCl3, CHCl3, CHF3, CH3Cl, CH3F, CH2F2, CH2Cl2, CFCl3, CF2Cl2, CF3Cl, CF4) in the vapor phase have been measured. For CCl4, CHCl3, CH2Cl2, and CH3Cl, which were previously studied by Das Gupta and Phillips, there is satisfactory agreement between the kq values obtained in the separate investigations. The linear dependence of the electron affinity of quencher with the corresponding quenching rate constants supports an exciplex mechanism in accordance with Klein's model. Charge transfer occurs from benzene to halogenated alkane and is greater for the chloro alkanes than for mixed fluoro–chloro alkanes. In the case of the triplet state of benzene, whose behaviour was monitored using the sensitized emission of biacetyl technique, quenching effects were at best one order of magnitude smaller and probably involve more than one bimolecular process.

Quenching rate constants for reactions of Ar(4p′[1/2]0, 4p[1/2]0, 4p[3/2]2, and 4p[5/2]2) atoms with 22 reagent gases

2001 ◽  
Vol 115 (7) ◽  
pp. 3144-3154 ◽  
Author(s):  
N. Sadeghi ◽  
D. W. Setser ◽  
A. Francis ◽  
U. Czarnetzki ◽  
H. F. Döbele
Keyword(s):  
Rate Constants ◽  
Quenching Rate

INTERSYSTEM CROSSING OF THE ELECTRONICALLY EXCITED DIDEUTEROETHYLENE MOLECULES FORMED IN BENZENE PHOTOSENSITIZATION

1966 ◽  
Vol 44 (18) ◽  
pp. 2173-2180 ◽  
Author(s):  
Terumi Terao ◽  
Shun-Ichi Hirokami ◽  
Shin Sato ◽  
R. J. Cvetanović
Keyword(s):  
Excited State ◽  
Experimental Evidence ◽  
Rate Constants ◽  
Intersystem Crossing ◽  
Molecular Decomposition ◽  
Electronically Excited

Experimental evidence is presented for a rapidly occurring intersystem crossing of the electronically excited dideuteroethylene molecules initially formed in the benzene-photosensitized reaction at 2 537 Å and 25 °C to another excited state which is responsible for the internal H-atom scrambling. The mechanism is entirely analogous to that previously postulated for the photoexcited states sensitized by Hg(3P1) atoms but the rate constants for intersystem crossing and molecular decomposition are drastically decreased as a result of the smaller amount of energy available for the excitation.

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