Zero-Phonon and Phonon-Assisted Radiative Transitions of Donor-Acceptor Pairs in Luminescent Semiconductors

The donor-acceptor radiative and Auger transitions have been investigated theoretically for the simple model of a direct semiconductor with parabolic bands and a random distribution of hydrogenic impurities. Both effects have been estimated as a function of donor-acceptor separation R , and expressions for the rates (when summed over all R ) have also been obtained. The results have been evaluated for GaAs at 80 K and for CdS at 1.6 K to facilitate comparison with experiment. The radiative calculations agree with the experimental results both as regards the numerical value in the limit R → 0 and also as regards the R -dependence. For the usual concentrations the radiative transitions are found to dominate in these materials. The Auger effect is likely to be a serious competitor only for electron collisions when n > 10 20 cm -3 .

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Non-Radiative Transitions in Metal-Free Octaethylporphyrin and 2-Nitrofluorene Donor-Acceptor System

10.26434/chemrxiv.6530570.v1 ◽

2018 ◽

Author(s):

Mihir Ghosh ◽

Shivraj ◽

B. Siddlingeshwar ◽

Anup Thomas ◽

Subrata Sinha

Keyword(s):

Electron Transfer ◽

Quantum Chemical Calculations ◽

Electronic Spectra ◽

Photoinduced Electron Transfer ◽

Quantum Chemical ◽

Metal Free ◽

Radiative Transitions ◽

Donor Acceptor

The aim of our work is to investigate the photoinduced electron transfer in non-covalent metal-free octaethyl porphyrin and 2 nitrofluorene system by electronic spectra and quantum chemical calculations.

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Recent Radiative and Collisional Atomic Data of Astrophysical Interest

International Astronomical Union Colloquium ◽

10.1017/s0252921100107596 ◽

1988 ◽

Vol 102 ◽

pp. 129-132

Author(s):

K.L. Baluja ◽

K. Butler ◽

J. Le Bourlot ◽

C.J. Zeippen

Keyword(s):

Mass Production ◽

Bound States ◽

Physical Models ◽

Impact Excitation ◽

Electron Impact Excitation ◽

Atomic Data ◽

Isoelectronic Sequence ◽

Astrophysical Interest ◽

Radiative Transitions ◽

Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

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