Energy ordering of singlet and triplet excitedstates in s-indacene, Pentalene,Cyclobutadiene derivatives in singlet fission : A model exact and density matrixrenormalization group study
Year: 2026
Type: preprint
Abstract: Specific molecules show an optimal energy configuration of singlet and triplet states due to the combination of anti-aromatic and aromatic components alongside bulky substituents.They exhibit longlasting triplet excitons and have appropriate structural modifications that make them particularly appealing for use in organic electronics and photovoltaics that rely on singlet fission (SF).Multiple examined molecules meet the energetic criteria necessary for singlet fission, with the differences E(S 1 ) -2E(T 1 ) and E(T 2 ) -2E(T 1 ) indicating an exothermic reaction and the presence of stable triplet excitons.We effectively utilized exact diagonalization along with the Symmetrized Density Matrix Renormalization Group (SDMRG) approach within the context of the correlated model Pariser-Parr-Pople (PPP) Hamiltonian to forecast low-lying excited states and energy levels in both singlet and triplet subspaces.These findings are then contrasted with results obtained from TDDFT, EOM-CCSD, CASPT2, and DMRG-SCF methods.The calculated values for the spin-orbit coupling constant in the triplet to singlet transition (T 1 → S 0 ) are quite low, which
Source: ChemRxiv
Authors: Ramen Patra, Mousumi Das
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220431257