Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission
Probing extended polyene systems with energy in excess of the bright state (1^1B+u/S2) band edge generates triplets via singlet fission. This process is not thought to involve the 2^1A−g/S1 state, suggesting that other states play a role. Using density matrix renormalization group (DMRG) calculation...
| প্রধান লেখক: | , , |
|---|---|
| বিন্যাস: | Journal article |
| ভাষা: | English |
| প্রকাশিত: |
American Physical Society
2020
|
| _version_ | 1826280773572886528 |
|---|---|
| author | Valentine, D Manawadu, D Barford, W |
| author_facet | Valentine, D Manawadu, D Barford, W |
| author_sort | Valentine, D |
| collection | OXFORD |
| description | Probing extended polyene systems with energy in excess of the bright state (1^1B+u/S2) band edge generates triplets via singlet fission. This process is not thought to involve the 2^1A−g/S1 state, suggesting that other states play a role. Using density matrix renormalization group (DMRG) calculations of the Pariser-Parr-Pople-Peierls Hamiltonian, we investigate candidate states that could be involved in singlet fission. We find that the relaxed 1^1B−u and 3^1A−g singlet states and 1^5A−g quintet state lie below the S2 state. The 1^1B−u, 3^1Ag, and 1^5A−g states are all thought to have triplet-pair character, which is confirmed by our calculations of bond dimerization, spin-spin correlation, and wave function overlap with products of triplet states. We thus show that there is a family of singlet excitations (i.e., 2^1A−g, 1^1B−u, 3^1A−g,⋯), composed of both triplet-pair and electron-hole character, which are fundamentally the same excitation, but have different center-of-mass energies. The lowest energy member of this family, the 2^1A−g state, cannot undergo singlet fission. But higher-energy members (e.g., the 3^1A−g) state, owing to their increased kinetic energy and reduced electron-lattice relaxation, can undergo singlet fission for certain chain lengths. |
| first_indexed | 2024-03-07T00:18:45Z |
| format | Journal article |
| id | oxford-uuid:7bc8f890-785b-4d3e-bf08-ffe3d93eee6c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:18:45Z |
| publishDate | 2020 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | oxford-uuid:7bc8f890-785b-4d3e-bf08-ffe3d93eee6c2022-03-26T20:52:47ZHigher energy triplet-pair states in polyenes and their role in intramolecular singlet fissionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7bc8f890-785b-4d3e-bf08-ffe3d93eee6cEnglishSymplectic ElementsAmerican Physical Society2020Valentine, DManawadu, DBarford, WProbing extended polyene systems with energy in excess of the bright state (1^1B+u/S2) band edge generates triplets via singlet fission. This process is not thought to involve the 2^1A−g/S1 state, suggesting that other states play a role. Using density matrix renormalization group (DMRG) calculations of the Pariser-Parr-Pople-Peierls Hamiltonian, we investigate candidate states that could be involved in singlet fission. We find that the relaxed 1^1B−u and 3^1A−g singlet states and 1^5A−g quintet state lie below the S2 state. The 1^1B−u, 3^1Ag, and 1^5A−g states are all thought to have triplet-pair character, which is confirmed by our calculations of bond dimerization, spin-spin correlation, and wave function overlap with products of triplet states. We thus show that there is a family of singlet excitations (i.e., 2^1A−g, 1^1B−u, 3^1A−g,⋯), composed of both triplet-pair and electron-hole character, which are fundamentally the same excitation, but have different center-of-mass energies. The lowest energy member of this family, the 2^1A−g state, cannot undergo singlet fission. But higher-energy members (e.g., the 3^1A−g) state, owing to their increased kinetic energy and reduced electron-lattice relaxation, can undergo singlet fission for certain chain lengths. |
| spellingShingle | Valentine, D Manawadu, D Barford, W Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title | Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title_full | Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title_fullStr | Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title_full_unstemmed | Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title_short | Higher energy triplet-pair states in polyenes and their role in intramolecular singlet fission |
| title_sort | higher energy triplet pair states in polyenes and their role in intramolecular singlet fission |
| work_keys_str_mv | AT valentined higherenergytripletpairstatesinpolyenesandtheirroleinintramolecularsingletfission AT manawadud higherenergytripletpairstatesinpolyenesandtheirroleinintramolecularsingletfission AT barfordw higherenergytripletpairstatesinpolyenesandtheirroleinintramolecularsingletfission |