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In this paper, we present dyadic adaptive HOPS (DadHOPS), a new method for calculating linear absorption spectra for large molecular aggregates. This method combines the adaptive HOPS (adHOPS) framework, which uses locality to improve computational scaling, with the dyadic HOPS method previously developed to calculate linear and nonlinear spectroscopic signals. To construct a local representation of dyadic HOPS, we introduce an initial state decomposition that reconstructs the linear absorption spectra from a sum over locally excited initial conditions. We demonstrate the sum over initial conditions can be efficiently Monte Carlo sampled and that the corresponding calculations achieve size-invariant [i.e., O(1)] scaling for sufficiently large aggregates while trivially incorporating static disorder in the Hamiltonian. We present calculations on the photosystem I core complex to explore the behavior of the initial state decomposition in complex molecular aggregates as well as proof-of-concept DadHOPS calculations on an artificial molecular aggregate inspired by perylene bis-imide to demonstrate the size-invariance of the method.
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This content will become publicly available on April 1, 2026
Benchmark Calculations for Near-Threshold Electron-Impact Excitation of the (1s3s)3,1S States of Helium
We revisit the current status of high-precision calculations for electron-impact excitation of the (1s3s)3,1S states in helium in the low-energy near-threshold regime that is characterized by a large number of resonance features. Having noticed discrepancies between predictions from two previous large-scale calculations for this problem, we report new results and make recommendations regarding the absolute cross-sections that should be used in modeling applications.
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- PAR ID:
- 10597978
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Atoms
- Volume:
- 13
- Issue:
- 4
- ISSN:
- 2218-2004
- Page Range / eLocation ID:
- 27
- Subject(s) / Keyword(s):
- electron scattering helium cross-section convergent close-coupling B-spline R-matrix
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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