Thermal broadening of the J-band in disordered linear molecular aggregates: A theoretical study
| dc.creator | Heijs, D. J. | |
| dc.creator | Malyshev, V. A. | |
| dc.creator | Knoester, J. | |
| dc.date | 2005-06-22 | |
| dc.date.accessioned | 2026-07-07T06:21:47Z | |
| dc.date.available | 2026-07-07T06:21:47Z | |
| dc.description | We theoretically study the temperature dependence of the J-band width in disordered linear molecular aggregates, caused by dephasing of the exciton states due to scattering on vibrations of the host matrix. In particular, we consider inelastic one- and two-phonon scattering between different exciton states (energy-relaxation-induced dephasing), as well as elastic two-phonon scattering of the excitons (pure dephasing). The exciton states follow from numerical diagonalization of a Frenkel Hamiltonian with diagonal disorder; the scattering rates between them are obtained using the Fermi Golden Rule. A Debye-like model for the one- and two-phonon spectral densities is used in the calculations. We find that, owing to the disorder, the dephasing rates of the individual exciton states are distributed over a wide range of values. We also demonstrate that the dominant channel of two-phonon scattering is not the elastic one, as is often tacitly assumed, but rather comes from a similar two-phonon inelastic scattering process. In order to study the temperature dependence of the J-band width, we simulate the absorption spectrum, accounting for the dephasing induced broadening of the exciton states. We find a power-law (T^p) temperature scaling of the effective homogeneous width, with an exponent p that depends on the shape of the spectral density of host vibrations. In particular, for a Debye model of vibrations, we find p ~ 4, which is in good agreement with experimental data on J-aggregates of pseudoisocyanine [J. Phys. Chem. A 101, 7977 (1997)]. | |
| dc.description | 14 pages, 7 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0506565 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0506565 | |
| dc.identifier | J. Chem. Phys. 123, 144507 (2005) | |
| dc.identifier | doi:10.1063/1.2052591 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/95712 | |
| dc.subject | Other Condensed Matter | |
| dc.title | Thermal broadening of the J-band in disordered linear molecular aggregates: A theoretical study | |
| dc.type | text |