Mechanism of external heavy-atom enhancement of the radiative transition rate from the π,π* triplet state

1973 ◽  
Vol 19 (4) ◽  
pp. 580-583 ◽  
Author(s):  
Tohru Azumi
Keyword(s):  
Triplet State ◽  
Transition Rate ◽  
Heavy Atom ◽  
Radiative Transition ◽  
Radiative Transition Rate

Enhanced quantum cutting luminescence by Au nanorods through improving radiative transition rate

2017 ◽  
Vol 402 ◽  
pp. 336-339 ◽  
Author(s):  
Biao Zheng ◽  
Lin Lin ◽  
Zhuohong Feng ◽  
Lili Huang ◽  
Luoqing Zhuang ◽  
...  
Keyword(s):  
Transition Rate ◽  
Radiative Transition ◽  
Au Nanorods ◽  
Quantum Cutting ◽  
Radiative Transition Rate

Collisional excitation of the formyl radical (HCO) by molecular hydrogen

2020 ◽  
Vol 498 (4) ◽  
pp. 5361-5366
Author(s):  
Paul J Dagdigian
Keyword(s):  
Accurate Determination ◽  
Radiative Transition ◽  
Rate Coefficients ◽  
Cluster Method ◽  
Quantum Scattering ◽  
Close Coupling ◽  
Explicitly Correlated ◽  
Radiative Transition Rate ◽  
Fine And Hyperfine Structure

ABSTRACT This paper addresses the need for accurate rate coefficients for transitions between fine- and hyperfine-structure resolved rotational transitions in the formyl (HCO) radical induced by collisions with the two nuclear spin modifications of H2, the dominant molecule in the interstellar medium (ISM). These rate coefficients, as well as radiative transition rate coefficients, are required for accurate determination of the abundance of HCO in the ISM. Time-independent close-coupling quantum scattering calculations have been used to compute rate coefficients for (de-)excitation of HCO in collisions with para- and ortho-H2. These calculations utilized a potential energy surface for the interaction of HCO with H2 recently computed by the explicitly correlated RCCSD(T)-F12a coupled-cluster method. Rate coefficients for temperatures ranging from 5 to 400 K were calculated for all transitions among the fine and hyperfine levels associated with the first 22 rotational levels of HCO, whose energies are less than or equal to 144 K.

scholarly journals Radiative and non-radiative transitions of excited Ti3+ cations in sapphire

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Avry Shirakov ◽  
Zeev Burshtein ◽  
Yehoshua Shimony ◽  
Eugene Frumker ◽  
Amiel A. Ishaaya
Keyword(s):  
Temperature Dependence ◽  
Electronic State ◽  
Fluorescence Lifetime ◽  
Radiative Lifetime ◽  
Radiative Transition ◽  
Zero Temperature ◽  
Thermal Phonon ◽  
Radiative Transitions ◽  
Thermal Enhancement ◽  
Radiative Transition Rate

AbstractWe have measured the fluorescence quantum efficiency in Ti3+:sapphire single crystals between 150 K and 550 K. Using literature-given effective fluorescence lifetime temperature dependence, we show that the zero temperature radiative lifetime is (4.44 ± 0.04) μs, compared to the 3.85 μs of the fluorescence lifetime. Fluorescence lifetime thermal shortening resolves into two parallel effects: radiative lifetime shortening, and non-radiative transition rate enhancement. The first is due to thermally enhanced occupation of a ΔE = 1,700 cm−1 higher (top) electronic state of the upper multiplet, exhibiting a transition oscillator strength of f = 0.62, compared to only 0.013 of the bottom electronic state of the same multiplet. The non-radiative rate relates to multi-phonon decay transitions stimulated by the thermal phonon occupation. Thermal enhancement of the configuration potential anharmonicity is also observed. An empiric expression for the figure-of-anharmonicity temperature dependence is given as $$\hat{{\bf{H}}}$$Hˆ (T) = $$\hat{{\bf{H}}}$$Hˆ (0)(1 + β exp(−ℏωco /kBT )), where $$\hat{{\bf{H}}}$$Hˆ (0) = 0.276, β = 5.2, ℏωco = 908 cm−1, and kB is the Boltzmann constant.

Löschung der Perylen-Fluoreszenz durch Ag+ -Ionen / Quenching of the Perylene Fluorescence by Ag+-Ions

1983 ◽  
Vol 38 (6) ◽  
pp. 698-700 ◽  
Author(s):  
H. Dreeskamp ◽  
A. Läufer ◽  
M. Zander
Keyword(s):  
Triplet State ◽  
Dynamic Process ◽  
Aromatic Compounds ◽  
Heavy Atom ◽  
Silver Ions ◽  
Intersystem Crossing ◽  
Fluid Solution ◽  
Long Wavelength ◽  
Wavelength Emission ◽  
Atom Effect

The fluorescence of perylene in fluid solution (λ0.0 = 440 nm) is quenched by silver ions in a dynamic process according to a Stern-Volmer kinetics (kq = 2 · 109 [1 • mol-1 · sec-1], in ethanol at 295 K). Simultaneously an unstructured long-wavelength emission (λmax ≈ 470 nm) appears which we assign to a perylene/Ag+ exciplex. A similar emission is observed when other polvcyclic aromatic compounds (PAC) are used, whose fluorescence as in the case of perylene is not easily quenched in an external heavy atom effect by iodopropane (kq ≦ 106). In these cases the excited PAC/Ag+ complex is long-lived enough to emit fluorescence since the intersystem crossing to the triplet system is slow due to the absence of an energetically favorable accepting triplet state

An exceptionally long-lived triplet state of red light-absorbing compact phenothiazine-styrylBodipy electron donor/acceptor dyads: a better alternative to the heavy atom-effect?

2020 ◽  
Vol 56 (11) ◽  
pp. 1721-1724 ◽  
Author(s):  
Yuqi Hou ◽  
Qingyun Liu ◽  
Jianzhang Zhao
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Electron Donor ◽  
Heavy Atom ◽  
Red Light ◽  
Intersystem Crossing ◽  
Spin Orbital ◽  
Heavy Atom Effect ◽  
Donor Acceptor ◽  
Atom Effect

Heavy atom-free dyads showing a red light-absorbing and exceptionally long-lived triplet state based on a spin–orbital charge transfer intersystem crossing mechanism.

Triplet state quantum yields for some arom atic hydrocarbons and xanthene dyes in dilute solution

1967 ◽  
Vol 299 (1458) ◽  
pp. 348-353 ◽  
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Triplet States ◽  
Dilute Solution ◽  
Perturbation Techniques ◽  
Excited Singlet ◽  
Xanthene Dyes ◽  
Extinction Coefficients

Quantum yields of triplet state formation and extinction coefficients of the triplet states have been determined by direct depletion methods for solutions of anthracene, phenanthrene, 1,2,5,6-dibenzanthracene, fluorescein, dibromofluorescein, eosin and erythrosin. The values obtained for the hydrocarbons are in reasonable agreement with those obtained by other workers using energy transfer and heavy atom perturbation techniques. In all cases which we have studied, the sum of the quantum yields of fluorescence and triplet state formation is equal to unity within the limits of experimental error, showing that radiationless transfer from the excited singlet to the ground state is negligible.

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