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Guidance for Mutual Disposition of Chromophores for Singlet Fission
Author(s) -
Havlas Zdenek,
Michl Josef
Publication year - 2016
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201500054
Subject(s) - chemistry , atomic orbital , chromophore , ethylene , singlet state , molecular orbital , fission , computational chemistry , matrix (chemical analysis) , singlet fission , simple (philosophy) , chemical physics , molecular physics , molecule , atomic physics , photochemistry , quantum mechanics , triplet state , physics , electron , organic chemistry , excited state , catalysis , chromatography , neutron , philosophy , epistemology
The choice of chromophores and of their mutual geometrical arrangement for optimized singlet fission (SF) rates are considered. The electronic matrix element that enters the Fermi golden rule for the rate of SF is worked out algebraically for a simple model, but the density of states factor is not analyzed here. The model treats only the highest occupied and lowest unoccupied orbitals of the partners. It provides an approximate formula that requires only the knowledge of the expansion coefficients of these orbitals and of overlap integrals between atomic orbitals on the partners to obtain an estimate of the electronic matrix element. An illustrative application to a pair of ethylene molecules suggests that favored geometries will be those in which one of the AOs on the first ethylene overlaps with both AOs on the second ethylene, while the other AO on the first ethylene overlaps with at least one, and preferably both, AOs of the second ethylene as little as possible.