辉石（链状硅酸盐）的室温红外光谱
Infrared Spectra of Pyroxenes (Crystalline Chain Silicates) at Room Temperature
摘要：
辉石晶体在陨石中很常见，但在天文环境中很少有成分被识别。我们提出了定量的室温光谱的17镁-铁-和钙-轴承原-和单斜辉石，和钙-辉石，以辨别趋势指示的晶体结构和广泛的组合物。使用金刚石砧盒产生数据：我们的带强度比在KBr或聚乙烯分散体中测量的带强度高6倍，其中包括数据处理中未解决的路径长度（来自粒度）和表面反射的变化。辉石具有多种光谱：顽火辉石（En $_{99}$）只有10.22~ $μ$ m和15.34~ $μ$ m两个谱带是所有辉石共有的。峰值波长通常随着Mg被Ca或Fe取代而增加。然而，当Fe组分从0增加到60%时，MgFe辉石中的两个谱带向较短波长移动，一个高强度谱带从11.6~ $μ$ m移动到11.2~ $μ$ m，当Fe增加到100%时，仍保持在11.2~ $μ$ m;它类似于通常识别为橄榄石或镁橄榄石的天文特征。在JWST获得的MIRI光谱中，在13~和16~ $μ$ m之间的独特辉石谱带显示出对它们进行鉴别的希望。如果用SPICA望远镜获得的数据，在40 ~ 80~ $μ$ m之间的许多辉石谱带可用于硅酸盐矿物学的诊断。我们的数据表明，顽火辉石和冷$\sim 10-K$天文尘埃特征的室温实验室波段在波长$\gtrsim 28~μ$ m的比较，可以导致识别（Mg，Fe）-辉石含有7- 15%的铁-比他们的真实值，因为一些温度变化模仿一些成分的变化。因此，一些天文硅酸盐可能含有比以前认为的更多的铁，更少的镁。
英文摘要：
Pyroxene crystals are common in meteorites but few compositions have been recognized in astronomical environments. We present quantitative room-temperature spectra of 17 Mg-- Fe-- and Ca--bearing ortho- and clinopyroxenes, and a Ca-pyroxenoid in order to discern trends indicative of crystal structure and a wide range of composition. Data are produced using a Diamond Anvil Cell: our band strengths are up to 6 times higher than those measured in KBr or polyethylene dispersions, which include variations in path length (from grain size) and surface reflections that are not addressed in data processing. Pyroxenes have varied spectra: only two bands, at 10.22~$μ$m and 15.34~$μ$m in enstatite (En$_{99}$), are common to all. Peak-wavelengths generally increase as Mg is replaced by Ca or Fe. However, two bands in MgFe-pyroxenes shift to shorter wavelengths as the Fe component increases from 0 to 60 per cent. A high-intensity band shifts from 11.6~$μ$m to 11.2~$μ$m and remains at 11.2~$μ$m as Fe increases to 100~per~cent; it resembles an astronomical feature normally identified with olivine or forsterite. The distinctive pyroxene bands between 13~ and 16~$μ$m show promise for their identification in MIRI spectra obtained with JWST. The many pyroxene bands between 40 and 80~$μ$m could be diagnositic of silicate mineralogy if data were obtained with the proposed SPICA telescope. Our data indicate that comparison between room-temperature laboratory bands for enstatite and cold $\sim 10-K$ astronomical dust features at wavelengths $\gtrsim 28~μ$m can result in the identification of (Mg,Fe)- pyroxenes that contain 7--15 % less Fe-- than their true values because some temperature shifts mimic some compositional shifts. Therefore some astronomical silicates may contain more Fe, and less Mg, than previously thought.
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