Long fluorescence lifetime of pyrazine vapors

Lahmani, F.; Frad, A.; Tramer, A.

doi:10.1016/0009-2614(72)80127-1

Cited by 28 publications

(4 citation statements)

References 16 publications

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“…These studies are important for generalization of the bifurcation concept and is directly relevant to the isomerization dynamics of one azine to another (e.g. pyrazine to pyrimidine), a subject which has been studied for many years. , …”

Section: Discussionmentioning

confidence: 99%

Femtosecond Dynamics of Pyridine in the Condensed Phase: Valence Isomerization by Conical Intersections

1999

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In this work, we combined femtosecond transient absorption (population and anisotropy) spectroscopy with ab initio electronic structure methods to study excited-state deactivation pathways of the pyridine molecule in liquid solutions. Studies of the effects of excitation energy, deuteration and substitution, solvent polarity and viscosity, and protonation of pyridine were performed. The experiments reveal the dynamics of S1(nπ*) and S2(ππ*) excited states of pyridine. The photoexcitation of the S2(ππ*) state leads to formation of the prefulvenic form of pyridine, a valence isomer, in ∼2.2 ps, while nonradiative deactivation of the S1(nπ*) state occurs in 9−23 ps and is to a large extent due to intersystem crossing. Using ab initio methods at the CASSCF and time-dependent DFT levels, we calculated the potential energy surfaces of the ground and S2(ππ*) states. A conical intersection was found responsible for the ultrafast deactivation of the pyridine molecule.

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Section: Discussionmentioning

confidence: 99%

Femtosecond Dynamics of Pyridine in the Condensed Phase: Valence Isomerization by Conical Intersections

1999

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“…9 In order to obtain an analytical solution of the multiple-state coupling problem, LTT makes a number of assumptions: (1) The state of the molecule immediately upon excitation is a pure zero-order single state |S). (2) The |S) state is coupled to an infinite manifold of triplet states |T) which are equally spaced in energy (spacing = e). (3) The matrix elements which couple |S) to |T) are all equal (Vst = V).…”

Section: Discussionmentioning

confidence: 99%

“…1949, 17, 1218. (2) Gouterman, M. "The Porphyrins"; Dolphin, D., Ed. ; Academic Press: New-York, 1978; Vol.…”

Section: Introductionmentioning

confidence: 99%

Rotational effects in the intermediate-case radiationless decay of pyrimidine

Bartels¹,

Spears²

1982

J. Phys. Chem.

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“…N XZsp (7) The excited state which is initially prepared by coherent excitation of the set of mixed states { In) } is identical with the zero-order singlet state [S). The subsequent change in [S) content of the excited state can be described approximately as a sum of two exponential decays, corresponding to fast (coherent) and slow (incoherent) decays, as given by Eqn (1).…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of Occurrence of Dual Fluorescence in Intermediate Case Molecules as Viewed From Rotational Effects

1987

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Fluorescence decays of jet-cooled pyrazine excited at various positions of rovibronic transitions within the 0-0 band were measured by the use of a pulsed dye laser pumped by an excimer or a nitrogen laser. The experimental data thus obtained on the number (N) of the triplet states coupled to the initially excited singlet rovibronic state were analyzed and interpreted by the aid of computer simulation using an asymmetric rotor program. The results indicate that the extraordinarily great variation of N with excitation energy and unreasonably small values of N hitherto reported in the literature can be understood in terms of the conventional theory based on the singlet-triplet mixed state model which has been developed for elucidating the mechanism of the occurrence of dual fluorescence in intermediate case molecules.

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Long fluorescence lifetime of pyrazine vapors

Cited by 28 publications

References 16 publications

Femtosecond Dynamics of Pyridine in the Condensed Phase: Valence Isomerization by Conical Intersections

Femtosecond Dynamics of Pyridine in the Condensed Phase: Valence Isomerization by Conical Intersections

Rotational effects in the intermediate-case radiationless decay of pyrimidine

The Mechanism of Occurrence of Dual Fluorescence in Intermediate Case Molecules as Viewed From Rotational Effects

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