We show that a stochastic approach enables calculations of the optical properties of large 2-dimensional and nanotubular excitonic molecular aggregates. Previous studies of such systems relied on numerically diagonalizing the dense and disordered Frenkel Hamiltonian, which scales approximately as $\mathcal{O}(N^3)$ for $N$ dye molecules. Our approach scales much more efficiently as $\mathcal{O}(N\log(N))$, enabling quick study of systems with a million of coupled molecules on the micron size scale. We calculate several important experimental observable including the optical absorption spectrum and density of states, and develop a stochastic formalism for the participation ratio. Quantitative agreement with traditional matrix diagonalization methods is demonstrated for both small- and intermediate-size systems. The stochastic methodology enables the study of the effects of spatial-correlation in site energies on the optical signatures of large 2D aggregates. Our results demonstrate that stochastic methods present a path forward for screening structural parameters and validating experiments and theoretical predictions in large excitonic aggregates.
Davydov-Type Excitonic Effects on the Absorption Spectra of Parallel-Stacked and Herringbone Aggregates of Pentacene: Time-Dependent Density-Functional Theory and Time-Dependent Density-Functional Tight Binding
Time-Dependent Density Matrix Renormalization Group Algorithms for Nearly Exact Absorption and Fluorescence Spectra of Molecular Aggregates at Both Zero and Finite Temperature
Nonuniform Screening Reshapes Collective Excitons in Molecular Aggregates from Stochastic Bethe-Salpeter Theory
Weizmann Institute of Science（魏茨曼科学研究所）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Princeton University（普林斯顿大学）；University of California, Los Angeles（加州大学洛杉矶分校）
Fragment-Based Configuration Interaction: Towards a Unifying Description of Biexcitonic Processes in Molecular Aggregates
Julius-Maximilians University Würzburg（维尔茨堡朱利叶斯-马克西米利安大学）；Center for Nanosystems Chemistry, Julius-Maximilians University Würzburg（维尔茨堡朱利叶斯-马克西米利安大学纳米系统化学中心）；Institute for Physical and Theoretical Chemistry, Julius-Maximilians University Würzburg（维尔茨堡朱利叶斯-马克西米利安大学物理与理论化学研究所）
Queens College, City University of New York（纽约市立大学皇后学院）；Graduate Center, City University of New York（纽约市立大学研究生院）；Goethe University Frankfurt（法兰克福歌德大学）；Institute of Chemistry, Academia Sinica（中央研究院化学研究所）；National Center for Theoretical Sciences（国家理论科学中心）；University of California, Riverside（加州大学河滨分校）
