用新方法从红外光谱直接推断分子结构,突破了依赖化学式的限制。
Data Fusion and Contrastive Alignment for Unconstrained IR Molecular Structure Elucidation

- 引入混合专家解码器和非加性聚合,更好处理复杂化学空间。
- 相比基线模型,Top-K准确率提升超10个百分点。
- 适合关注AI辅助分析化学、分子结构解析的研究者。
近年来,自动化红外(IR)光谱分子结构解析取得显著进展,但其广泛应用受限于需预先提供化学式作为辅助输入,导致模型仅能识别异构体而非完整分子结构。尽管变压器模型在异构体识别上表现优异,但在无约束结构解析中可靠性较低且机制不明确。本文提出并评估了传统编码器-解码器变压器的关键改进:为应对无约束问题的庞大化学空间,引入新型混合专家(MoE)解码模块,采用线性序统计与Choquet积分实现非加性聚合;同时将此类非加性算子应用于光谱表征聚合过程。结合辅助对比对齐损失项,该方法使Top-K预测准确率较仅使用红外光谱的基线模型提升超过10个百分点。通过子结构片段分析,进一步证实红外光谱蕴含绝大多数相关化学信息,说明异构体排序模型性能更高主要源于所探索化学空间中吸收带重叠或代表性不足。本研究证明了仅凭实测红外光谱实现自动化分子结构解析的有效性,显著拓展了人工智能在分析化学中的应用前景。
原文摘要 · Abstract (English)
Automated molecular structure elucidation from infrared (IR) spectroscopy data has seen significant advancements in recent years, but its broad applicability is limited by a reliance on pre-determined chemical formulas provided as auxiliary model inputs. This limits model predictions to isomer identification rather than full molecular structure prediction. Although transformer models have been shown to identify molecular isomers with high accuracy, their reliability for unconstrained structure elucidation is comparatively low and poorly understood. In this work, we propose and evaluate key modifications to the traditional encoder-decoder transformer. To better address the vast chemical space of the unconstrained problem, we implement a novel Mixture-of-Experts (MoE) decoder module that utilizes non-additive aggregation via linear-order statistics and the Choquet integral. We further modify the transformer to utilize these non-additive operators when aggregating spectral representations as well. Together with an auxiliary contrastive alignment loss term, these enhancements improve Top-K prediction accuracy by over 10 percentage points compared to baseline IR-only models. Through sub-structure fragment analysis of molecular predictions, we further confirm that infrared spectra encode the vast majority of relevant chemical information, implying that the higher performance of isomer-ranking models is largely due to underrepresented or overlapping absorption bands for molecules in the explored chemical space. Ultimately, by demonstrating the efficacy of automated molecular structure elucidation from measured IR spectra, this work serves to significantly broaden the utility of AI in analytical chemistry.
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