Chemically Resolved Topological Coordinates Link Structural Dynamics and Configurational Thermodynamics
Abstract
Atomic coordinates specify a structure, but they do not reveal how chemical connectivity across several length scales relates to atomic motion and configurational energy ordering. We formulate chemically directed persistent homology at four resolutions---complete networks, individual sites, spatial fields, and substitutional arrangements---while retaining the chemical identity and length scale of each connectivity feature. In \textit{ab initio} molecular dynamics (AIMD) trajectories of δ- and γ-CsPbI3 at five temperatures spanning 500--700 K, the corner-sharing γ network has a lower Pb--I restoring stiffness and permits larger iodide excursions, yet iodide positional correlations decay 2.27 times more slowly and Pb-network topology retains memory 1.63 times longer than in the edge-sharing δ phase. Local softness and loss of network memory are therefore distinct. At individual sites, rare γ-phase Pb environments with a δ-like Cs-cage connectivity precede 0.17 mathringA greater Pb displacement over the subsequent 0.5 ps. The same Pb-network coordinate resolves disruption of corner-sharing connectivity across a 2560-atom δ|γ boundary. In substituted CsPbI3, compact dopant arrangements undergo greater cooperative host relaxation and lie lower in density-functional-theory (DFT) energy than dispersed arrangements of the same composition. SchNet and Allegro model families with comparable energy errors encode opposite ordering along this coordinate, and 61 of 247 supplied models with errors below 1 meV atom−1 on separate test structures reverse the DFT relation. Because relative configurational energies set Boltzmann populations, chemical network topology links structure to physical response and tests whether learned energy models preserve DFT configurational ordering even when their average errors are small.
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BibTeX
@misc{pandey2026chemically,
title = {{Chemically Resolved Topological Coordinates Link Structural Dynamics and Configurational Thermodynamics}},
author = {Ayush Kumar Pandey and Abhishek Tewari},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.30523},
eprint = {2608.30523},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.30523},
}
RIS
TY - UNPB
TI - Chemically Resolved Topological Coordinates Link Structural Dynamics and Configurational Thermodynamics
AU - Ayush Kumar Pandey
AU - Abhishek Tewari
PY - 2026
DA - 2026/08/31
PB - arXiv
DO - 10.48550/arxiv.2608.30523
UR - https://arxiv.org/abs/2608.30523
AB - Atomic coordinates specify a structure, but they do not reveal how chemical connectivity across several length scales relates to atomic motion and configurational energy ordering. We formulate chemically directed persistent homology at four resolutions---complete networks, individual sites, spatial fields, and substitutional arrangements---while retaining the chemical identity and length scale of each connectivity feature. In \textit{ab initio} molecular dynamics (AIMD) trajectories of δ- and γ-CsPbI_3 at five temperatures spanning 500--700 K, the corner-sharing γ network has a lower Pb--I restoring stiffness and permits larger iodide excursions, yet iodide positional correlations decay 2.27 times more slowly and Pb-network topology retains memory 1.63 times longer than in the edge-sharing δ phase. Local softness and loss of network memory are therefore distinct. At individual sites, rare γ-phase Pb environments with a δ-like Cs-cage connectivity precede 0.17 mathringA greater Pb displacement over the subsequent 0.5 ps. The same Pb-network coordinate resolves disruption of corner-sharing connectivity across a 2560-atom δ|γ boundary. In substituted CsPbI_3, compact dopant arrangements undergo greater cooperative host relaxation and lie lower in density-functional-theory (DFT) energy than dispersed arrangements of the same composition. SchNet and Allegro model families with comparable energy errors encode opposite ordering along this coordinate, and 61 of 247 supplied models with errors below 1 meV atom^−1 on separate test structures reverse the DFT relation. Because relative configurational energies set Boltzmann populations, chemical network topology links structure to physical response and tests whether learned energy models preserve DFT configurational ordering even when their average errors are small.
ER -