AI 中文总结
该研究旨在获取含脂肪族芘衍生物的红外发射光谱并与天文观测比较。通过记录不同温度下的中红外光谱，结合模型模拟并与实际观测对比，提出六氢芘是3.4μm带红色成分载体，相关光谱数据存于新数据库，增进对该波段发射贡献的理解。
AI 中文摘要
在3.3μm处的芳香红外发射带观测中，常能在3.4 - 3.6μm范围内发现卫星发射特征。3.3μm带归因于多环芳烃（PAHs）的CH伸缩振动，而卫星带，尤其是突出的3.4μm成分，被认为是氢化和甲基化PAH类物种中的脂肪族CH伸缩振动所致。研究旨在获取含脂肪族芘衍生物的最新红外发射光谱并与天文观测作比较，以增进对这些物种对3.4μm发射带贡献的理解。记录了气相二氢芘、四氢芘、六氢芘、甲基化芘和芘在373至673K温度下的中红外光谱（1.4 - 25μm），用多组分拟合工具分析带轮廓并得出经验非谐性定律以量化带位置和宽度随温度的变化。将所得光谱数据与蒙特卡罗发射模型结果结合，模拟紫外光子吸收后的发射光谱直至解离极限（约6eV）。将合成光谱与詹姆斯·韦伯太空望远镜对猎户座棒状区域（PDRs4All计划）的观测进行比较。基于这些最新模拟光谱，提出1,2,3,6,7,8 - 六氢芘是在3.403μm处观测到的3.4μm带红色成分的载体。1 - 甲基芘也可能对潜在发射平台有贡献，但其缺乏强红外带，与六氢芘不同，这使其在观测光谱中检测复杂。所有实验光谱及其温度相关分析都可在新的cosmicPAH - IRDB数据库中获取。
英文摘要
Observations of the aromatic infrared emission band at 3.3 $μ$m often reveal satellite emission features in the 3.4 - 3.6 $μ$m range. While the 3.3 $μ$m band is attributed to the CH stretching vibration of polycylic aromatic hydrocarbons (PAHs), the satellite bands - particularly its prominent 3.4 $μ$m component - is assigned to aliphatic CH stretching vibrations in hydrogenated and methylated PAH-like species. Our aim is to derive state-of-the-art infrared emission spectra for aliphatic-containing pyrene derivatives and compare them with astronomical observations. This will help refine our understanding of the contribution of these species to the 3.4 $μ$m emission band. Mid-infrared spectra (1.4-25 $μ$m) of gas-phase dihydropyrene, tehtrahydropyrene, hexahydropyrene methylated pyrene, and pyrene were recorded at temperatures ranging from 373 to 673 K, depending on the species. The band profiles were analyzed using a multi-component fitting tool, and empirical anharmonicity laws were derived to quantify the evolution of the band positions and widths with temperature. The obtained spectral data was combined with the results of a Monte Carlo emission model to simulate the emission spectra following UV-photon absorption, up to the dissociation limit ($\lesssim$6 eV). The resulting synthetic spectra were compared with James Webb Space Telescope observations of the Orion Bar region (PDRs4All program). Based on these state-of-the-art simulated spectra, we propose 1,2,3,6,7,8-hexahydropyrene as the carrier of the red component of the 3.4 $μ$m band observed at 3.403 $μ$m. While 1-methylpyrene may also contribute to the underlying emission plateau, its lack of a strong infrared band complicates detection in observed spectra, unlike hexahydropyrene. All experimental spectra and their temperature-dependent analyses are available in the new cosmicPAH-IRDB database.
Comments19 pages, 21 figures
