Collisional Deactivation Rates of Electronically Excited Molecular Ions. II

1972 ◽  
Vol 50 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. I. Mackay ◽  
R. E. March
Keyword(s):  
Rate Constants ◽  
Radiative Lifetime ◽  
Molecular Ions ◽  
Deactivation Rate ◽  
Complete Knowledge ◽  
Induced Dipole ◽  
Excited Species ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Deactivation Rate Constant

Total deactivation rate constants have been determined for N2+(B2Σu+) and the (A2Πu) and (B2Σu+) states of CO2+ with a number of quenchers. The energy specific total deactivation rate constant is compared to the total radiative lifetime of the excited species. A particular novelty of the technique is that it does not require a complete knowledge of the formation modes for the excited species. The results are compared with theoretical values obtained from the ion-induced dipole model. Individual deactivation rate constants are presented for N2+(B2Σu+) ions in the v = 0, 1, and 2 vibrational levels quenched by N2, O2, H2, and CO2; and for the(A2Πu) and (B2Σu+) states of CO2+ quenched byCO2, N2, O2, NO, and H2. Charge transfer is the most probable mode of deactivation except in the CO2+–H2 reactions where H-atom abstraction is more probable.

Collisional Deactivation Rates of N2+ (B2Σu+)

1971 ◽  
Vol 49 (8) ◽  
pp. 1268-1271 ◽  
Author(s):  
G. I. Mackay ◽  
R. E. March
Keyword(s):  
Electron Beam ◽  
Charge Transfer ◽  
Rate Constants ◽  
Electron Beam Excitation ◽  
Vibrational Levels ◽  
Most Probable Mode ◽  
Electronically Excited ◽  
State Charge ◽  
Beam Excitation

Electron beam excitation of nitrogen was utilized to produce ions in the zeroth and first vibrational levels of the B2Σu+ state. The rate constants for the collisional deactivation of electronically excited N2+, for each of N2 and NO, were determined individually for the v′ = 0 and v′ = 1 vibrational levels of the N2+(B2Σu+) state. Charge transfer is the most probable mode of deactivation.

Collisional Deactivation Rates of Electronically Excited Molecular Ions. III.

1972 ◽  
Vol 50 (15) ◽  
pp. 2516-2517
Author(s):  
G. I. Mackay ◽  
J. P. Anglesey ◽  
R. E. March
Keyword(s):  
Electron Beam ◽  
Charge Transfer ◽  
Rate Constants ◽  
Molecular Ions ◽  
Electron Beam Excitation ◽  
Electronically Excited ◽  
State Rate ◽  
Beam Excitation

Electron beam excitation of oxygen was utilized to produce ions in the [Formula: see text] state. Rate constants for the deactivation of [Formula: see text] for each of O2 and N2 were determined. Charge transfer is a possible mode of deactivation.

The OH Meinel bands in the airglow—the radiative lifetime

1978 ◽  
Vol 56 (5) ◽  
pp. 581-586 ◽  
Author(s):  
E. J. Llewellyn ◽  
B. H. Long
Keyword(s):  
Rate Constants ◽  
Rotational Temperature ◽  
Radiative Lifetime ◽  
Rotational Relaxation ◽  
Vibrational Levels

A model of the rotational relaxation of an emitting population has been used to determine the rotational temperature of emitted spectra for the OH Meinel bands. It is shown that the calculated rotational temperatures for these spectra are consistent with laboratory observations of the hydrogen–ozone reaction if the radiative lifetime for the Meinel bands is short, [Formula: see text]The model is also used to infer the initial rotational populations of the OH vibrational levels excited in the hydrogen–ozone reaction. It has been found that these initial rotational populations may be described by rotational temperatures of 1940, 1230, and 760 K for the seventh, eighth, and ninth vibrational levels, respectively. It is also concluded that the rate constants for vibrational quenching will be increased from previously accepted values. The effect of a short radiative lifetime for airglow observations is also discussed.

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.

Deactivation of O(1S) and O2(b1Σg+)

1969 ◽  
Vol 47 (10) ◽  
pp. 1870-1877 ◽  
Author(s):  
F. Stuhl ◽  
K. H. Welge
Keyword(s):  
Rate Constants ◽  
Excited Species ◽  
Intensity Decay

Rate constants for the collisional deactivation of O(1S) and O2(b1Σg+) are reported. They are obtained by measuring the intensity decay of the O(1S → 1D) and O2(b1Σg+ → X2Σg+) emissions after a pulsed production of the excited species.

Unimolecular decay paths of electronically excited species. VI. The Ã2E state of NH+3

1985 ◽  
Vol 82 (9) ◽  
pp. 4073-4075 ◽  
Author(s):  
C. Krier ◽  
M. Th. Praet ◽  
J. C. Lorquet
Keyword(s):  
Excited Species ◽  
Electronically Excited

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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