REAP: Towards Effective Training-Free Chemical Reasoning with Explicit Atomic Priors

Mingxu Zhang, Dazhong Shen, Qi Zhang, Ying Sun


Abstract
Large Language Models (LLMs) exhibit strong general reasoning but struggle in molecular science due to the lack of explicit priors required for precise chemical reasoning. Current solutions inject priors into parameters, but this static coupling hinders rapid knowledge updates and often compromises the model’s general capabilities. To address this, we introduce REAP, a training-free framework that equips LLMs with an external knowledge base, enabling them to reason over retrieved chemical priors dynamically. REAP implements a structured reasoning pipeline that autonomously selects relevant priors from our constructed atom-level knowledge base, retrieves analogue exemplars, and synthesizes these information to guide the LLM’s decision-making. This architecture ensures interpretability and adaptability while preserving the LLM’s intrinsic general intelligence. Experiments show that REAP outperforms current reasoning methods and rivals state-of-the-art training-based models, demonstrating the effectiveness of our framework.
Anthology ID:
2026.findings-acl.97
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
2037–2062
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.97/
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Cite (ACL):
Mingxu Zhang, Dazhong Shen, Qi Zhang, and Ying Sun. 2026. REAP: Towards Effective Training-Free Chemical Reasoning with Explicit Atomic Priors. In Findings of the Association for Computational Linguistics: ACL 2026, pages 2037–2062, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
REAP: Towards Effective Training-Free Chemical Reasoning with Explicit Atomic Priors (Zhang et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.97.pdf
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