scholarly journals Nonradiative decay of the lowest excited singlet state of 2-aminopyridine is considerably faster than the radiative decay

2009 ◽  
Vol 130 (14) ◽  
pp. 144315 ◽  
Author(s):  
Feng Zhang ◽  
Yue-Jie Ai ◽  
Yi Luo ◽  
Wei-Hai Fang
Keyword(s):  
Radiative Decay ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Nonradiative Decay

Vibrational energy dependence of radiationless conversion in aromatic vapours

1974 ◽  
Vol 340 (1623) ◽  
pp. 519-533 ◽  
Keyword(s):  
Fluorescence Lifetime ◽  
Radiative Decay ◽  
Vibrational Energy ◽  
Singlet State ◽  
Vibrational Excitation ◽  
Excited Singlet State ◽  
Fluorescence Lifetimes ◽  
Excited Singlet ◽  
Decay Probability ◽  
Length Changes

Under collision-free conditions the fluorescence lifetimes of naphthalene, 1-2 benzanthracene, chrysene and pyrene decrease with increasing excitation energy within the first excited singlet state. In anthracene the fluorescence lifetime is constant within the first excited singlet state. An explanation of these findings in terms of bond length changes between the excited singlet state and the first triplet state, and also the symmetry of the first singlet state is given. The effect of added foreign gas on fluorescence lifetimes and triplet yields is discussed in terms of a model which allows the non-radiative decay probability to vary with the degree of vibrational excitation. Excellent agreement is obtained with the experimental results on naphthalene fluorescence. The decrease of triplet yield as foreign gas pressure is reduced is also interpreted in terms of this model.

Intermediate level structure in highly excited electronic states of large molecules

1972 ◽  
Vol 327 (1570) ◽  
pp. 367-391 ◽  
Keyword(s):  
Excited State ◽  
Radiative Decay ◽  
Singlet State ◽  
Electronic States ◽  
Intermediate Level ◽  
Excited Singlet State ◽  
Large Molecule ◽  
Level Spacing ◽  
Excited Electronic States ◽  
Excited Singlet

In this paper we consider the radiative decay of excited electronic states of a large molecule which correspond to the dense intermediate level spacing situation, encountered for the second excited singlet state of some aromatic hydrocarbons, which is separated from the first excited singlet state by a small (3000 to 4000 cm -1 ) electronic energy gap. Intramolecular interstate coupling and the interaction with the radiation field were handled by a selfconsistent extension of the Wigner-Weisskopf approximation. We were able to derive a general expression for the time and energy resolved decay spectrum of a highly excited state of a large molecule, which yields information concerning the decay pattern, for the fluorescence lifetime(s) and for the corresponding quantum yields, in different spectral regions. Weak and strong coupling limits can be distinguished and defined in terms of the magnitude of the non-adiabatic interstate coupling terms relative to the spacing and the width of the zero states. In the intermediate level spacing in a large molecule, the radiative decay of the excited state should be considered in terms of the decay of a finite set of coupled levels and intramolecular relaxation between these states does not occur in the ‘isolated’ molecule. Resonance fluorescence is amenable to experimental observation from the second excited singlet state of a large molecule which corresponds to this intermediate case. The weak and strong coupling situations can be experimentally distinguished on the basis of energy resolved lifetime measurements. General criteria have been provided for the observation of quantum interference effects in the radiative decay for different coupling schemes. The present theoretical results provide a proper interpretation of some recent experimental data concerning the radiative decay of the second excited state of some aromatic molecules (3,4-benzpyrene and naphthalene).

The Gold Porphyrin First Excited Singlet State¶

2002 ◽  
Vol 76 (1) ◽  
pp. 47 ◽  
Author(s):  
Joakim Andréasson ◽  
Gerdenis Kodis ◽  
Su Lin ◽  
Ana L. Moore ◽  
Thomas A. Moore ◽  
...  
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet

The Forbidden 11Bu– Excited Singlet State in Peridinin and Peridinin Analogues

2017 ◽  
Vol 122 (1) ◽  
pp. 130-139
Author(s):  
Jordan A. Greco ◽  
Nicole L. Wagner ◽  
Harry A. Frank ◽  
Robert R. Birge
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet
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