Triplet-State Formation along the Ultrafast Decay of Excited Singlet Cytosine

2005 ◽  
Vol 127 (6) ◽  
pp. 1820-1825 ◽  
Author(s):  
Manuela Merchán ◽  
Luis Serrano-Andrés ◽  
Michael A. Robb ◽  
Lluís Blancafort
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Excited Singlet

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.

Triplet state formation efficiencies of aromatic hydrocarbons in solution

1968 ◽  
Vol 306 (1485) ◽  
pp. 257-273 ◽  
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Aromatic Hydrocarbons ◽  
Rate Constants ◽  
Internal Conversion ◽  
Transition Probability ◽  
Radiative Transition ◽  
Excited Singlet ◽  
Radiative Transitions ◽  
Solvent Systems

The triplet state formation efficiencies,ф T , of ten aromatic hydrocarbons have been deter­mined in ethanol and, in some cases, in other solvents. Fluorescence yields, ф F , for the various hydrocarbon-solvent systems were measured where literature values were not available. With the exception of coronene the sum of ф F + ф T was found to be unity within experi­mental error, which indicates little or no internal conversion from the first excited singlet state of each hydrocarbon. Rate constants for intersystem crossing, k IS and the ratio k IS / k F , where k F is the radiative transition probability, have been calculated for each hydrocarbon in ethanol. The ratio varies much less than do the separate rate constants and the significance of this is discussed in terms of possible selection rules for spin forbidden non-radiative transitions.

The radiation-induced formation of excited states of aromatic hydrocarbons in benzene and cyclohexane. III. Effect of singlet state quenchers

1972 ◽  
Vol 328 (1575) ◽  
pp. 481-496 ◽  
Keyword(s):  
Triplet State ◽  
Excited States ◽  
State Formation ◽  
Aromatic Hydrocarbons ◽  
Extinction Coefficient ◽  
Singlet State ◽  
Excited Singlet State ◽  
Intersystem Crossing ◽  
Excited Singlet ◽  
Radiation Induced

The contribution to naphthalene and pyrene triplet state formation of intersystem crossing from the excited singlet state has been determined for both cyclohexane and benzene solutions using the singlet state quenchers nitromethane and xenon. In agreement with the conclusions reported in part II, intersystem crossing plays an important role; under certain conditions up to 50 % of the total triplet yield in naphthalene-cyclohexane solutions has this origin. The extinction coefficient for naphthalene triplet absorption in cyclohexane at λ max = 412.5 nm is 20 000 ± 5000 1 mol -1 cm -1 .

Effect of Aggregation on Bacteriochlorin a Triplet-state Formation: A Laser Flash Photolysis Study¶

2002 ◽  
Vol 76 (5) ◽  
pp. 480 ◽  
Author(s):  
Xavier Damoiseau ◽  
Francis Tfibel ◽  
Maryse Hoebeke ◽  
Marie-Pierre Fontaine-Aupart
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

2015 ◽  
Vol 119 (15) ◽  
pp. 8095-8102 ◽  
Author(s):  
Venugopal Bandi ◽  
Habtom B. Gobeze ◽  
Vellanki Lakshmi ◽  
Mangalampalli Ravikanth ◽  
Francis D’Souza
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Charge Separation ◽  
Charge Recombination

Photolysis of ketene. I

1968 ◽  
Vol 46 (14) ◽  
pp. 2353-2360 ◽  
Author(s):  
A. N. Strachan ◽  
D. E. Thornton
Keyword(s):  
Carbon Monoxide ◽  
Quantum Yield ◽  
Triplet State ◽  
Singlet State ◽  
Inert Gases ◽  
Inert Gas ◽  
Excited Singlet State ◽  
Intersystem Crossing ◽  
Excited Singlet ◽  
Increasing Temperature

Ketene has been photolyzed at 3660 and 3130 Å both alone and in the presence of the inert gases C4F8 and SF6. The quantum yield of carbon monoxide has been determined at both wavelengths as a function of pressure and temperature. At 3660 Å the quantum yield decreases with increasing pressure but increases with increasing temperature. At 3130 Å the quantum yield with ketene alone remains 2.0 at both 37 and 100 °C at pressures up to 250 mm. At higher pressures of ketene or with added inert gas the quantum yield decreases with increasing pressure. The results are interpreted in terms of a mechanism in which intersystem crossing from the excited singlet state to the triplet state occurs at both wavelengths, and collisional deactivation of the excited singlet state by ketene is single stage at 3660 Å but multistage at 3130 Å.

Time-Resolved EPR Study of Photoexcited Triplet-State Formation in Electron-Donor-Substituted Acridinium Ions

1996 ◽  
Vol 100 (9) ◽  
pp. 3312-3316 ◽  
Author(s):  
Hans van Willigen ◽  
Guilford Jones ◽  
Mohammad S. Farahat
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Electron Donor ◽  
Time Resolved

scholarly journals Charge-transfer heptamethine dyes for NIR singlet oxygen generation

2019 ◽  
Vol 55 (38) ◽  
pp. 5511-5514 ◽  
Author(s):  
John B. Jarman ◽  
Dennis A. Dougherty
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Singlet Oxygen ◽  
State Formation ◽  
Charge Transfer State ◽  
Previous Evidence ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
A Charge ◽  
Transfer State

A heptamethine-based charge-transfer dye was designed based on previous evidence of triplet state formation in orthogonal charge-transfer partners and calculations suggesting the formation of a charge-transfer state in heptamethine dye derivatives.

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