Quantum yield internal conversion

The external quantiun yield or I PC E (incident photon to current efficiency) is defined as the quotient of the number of incident photons and the number of charge carriers output to the external circuit. It is smaller than the internal quantum yield for conversion of the absorbed photons into charge carriers within the cell, because it takes into account losses due to reflection, recombination, and scattering. In contrast to the internal quantum yield, which can attain values of nearly 100% (see above), the value of the external quantum yield can be measured directly from the short-circuit current density jsc. with jsc = Isc/A where A is the active area of the cell, and the incident light intensity is lo- At a given wavelength k, we have... 

Any mechanism which involves isoenergetic, radiationless internal conversion from C, P, or T to a high vibrational level of the ground state would be expected to show a large deuterium isotope effect on the rate of internal conversion. In the direct photolysis of perdeuterio and perhydrostilbene, Saltiel<8a) found no isotope effect on the photostationary state or upon the quantum yields of cis-to-trans and trans-to-cis conversion. 

Quenching rate constants for dienes and quadricyclenes have similar sensitivities to the electronic and structural features of the excited aromatic hydrocarbon. However, during this process quadricyclene isomerizes to nor-boraadiene with a quantum yield of 0.52, whereas dienes usually remain unchanged/10 Hammond has suggested that vibrational energy which is partitioned to the acceptor upon internal conversion of the exciplex can lead to isomerization(10a,103) ... 

Kummer AD, Kompa C, Lossau H, Pollinger-Dammer F, Michel-Beyerle ME, Silva CM, Bylina EJ, Coleman WJ, Yang MM, Youvan DC (1998) Dramatic reduction in fluorescence quantum yield in mutants of green fluorescent protein due to fast internal conversion. Chem Phys 237 183-193... 

When a molecule is in the S v = 0) state, fluorescence emission is only one of the several competing physical processes by which the molecule can return to the ground state. A molecule in Si(v = 0) can undergo fluorescence, intersystem crossing or internal conversion, which have rate quantum yields < >f, (j) sc and respectively and ... 

Recently, it was shown that in deuterated tetraphenylporphin the fluorescence quantum yield and lifetime, and the triplet yield increase in a similar manner relative to the undeuterated one (24). Such a deuterium isotope effects on the state suggested the participation of Sq internal conversion in the energy dissipating... 

Fluorescence Lifetimes (T ), Fluorescence Quantum Yields (0f), Triplet Quantum Yields (0 ), and Quantum Yields of Internal Conversion... 

As the absorption spectra did not change after laser light irradiation, no appreciable reaction seems to occur through the state. Thus, the decay processes from the state can be assumed to be only fluorescence, intersystem crossing, and internal conversion. The quantum yields of internal conversion ( are, therefore, estimated by the following equation ... 

Using the values of quantum yields and fluorescence lifetime, rate constants on the state were obtained. The results are summarized in "Table III". As seen in "Table III", no isotope effect is observed in the rate constants for the fluorescence and intersystem crossing. On the other hand, in the case of TPP the rate constants of internal conversion show a large isotope effect that of D2TPP is... 

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