Hawaii Institute of Geophysics and Planetology, University of Hawaii, 1680 East-West Road, POST 602, Honolulu, HI 96822, USA.
Philos Trans A Math Phys Eng Sci. 2010 Jul 13;368(1922):3167-91. doi: 10.1098/rsta.2010.0034.
We report time-resolved (TR) remote Raman spectra of minerals under supercritical CO(2) (approx. 95 atm pressure and 423 K) and under atmospheric pressure and high temperature up to 1003 K at distances of 1.5 and 9 m, respectively. The TR Raman spectra of hydrous and anhydrous sulphates, carbonate and silicate minerals (e.g. talc, olivine, pyroxenes and feldspars) under supercritical CO(2) (approx. 95 atm pressure and 423 K) clearly show the well-defined Raman fingerprints of each mineral along with the Fermi resonance doublet of CO(2). Besides the CO(2) doublet and the effect of the viewing window, the main differences in the Raman spectra under Venus conditions are the phase transitions, the dehydration and decarbonation of various minerals, along with a slight shift in the peak positions and an increase in line-widths. The dehydration of melanterite (FeSO(4).7H(2)O) at 423 K under approximately 95 atm CO(2) is detected by the presence of the Raman fingerprints of rozenite (FeSO(4).4H(2)O) in the spectrum. Similarly, the high-temperature Raman spectra under ambient pressure of gypsum (CaSO(4).2H(2)O) and talc (Mg(3)Si(4)O(10)(OH)(2)) indicate that gypsum dehydrates at 518 K, but talc remains stable up to 1003 K. Partial dissociation of dolomite (CaMg(CO(3))(2)) is observed at 973 K. The TR remote Raman spectra of olivine, alpha-spodumene (LiAlSi(2)O(6)) and clino-enstatite (MgSiO(3)) pyroxenes and of albite (NaAlSi(3)O(8)) and microcline (KAlSi(3)O(8)) feldspars at high temperatures also show that the Raman lines remain sharp and well defined in the high-temperature spectra. The results of this study show that TR remote Raman spectroscopy could be a potential tool for exploring the surface mineralogy of Venus during both daytime and nighttime at short and long distances.
我们报告了在超临界 CO2（约 95 大气压和 423 K）和常压及高温下（高达 1003 K）分别在 1.5 和 9 m 距离下矿物的时间分辨（TR）远程拉曼光谱。在超临界 CO2（约 95 大气压和 423 K）下，含水和无水硫酸盐、碳酸盐和硅酸盐矿物（例如滑石、橄榄石、辉石和长石）的 TR 拉曼光谱清晰地显示了每种矿物的明确拉曼指纹，以及 CO2 的费米共振双峰。除了 CO2 双峰和观察窗的影响之外，在金星条件下拉曼光谱的主要差异是各种矿物的相变、脱水和脱碳，以及峰位的轻微位移和线宽的增加。在大约 95 大气压的 CO2 下，在 423 K 时检测到蓝铁矿（FeSO4·7H2O）的脱水作用，这是通过光谱中出现针铁矿（FeSO4·4H2O）的拉曼指纹来证明的。同样，在常压下石膏（CaSO4·2H2O）和滑石（Mg3Si4O10（OH）2）的高温拉曼光谱表明，石膏在 518 K 时脱水，但滑石在 1003 K 时仍保持稳定。白云石（CaMg（CO3）2）在 973 K 时发生部分分解。橄榄石、α-锂辉石（LiAlSi2O6）和斜顽辉石（MgSiO3）辉石以及钠长石（NaAlSi3O8）和微斜长石（KAlSi3O8）长石的 TR 远程拉曼光谱在高温下也表明，拉曼线在高温光谱中仍然保持尖锐和明确。本研究的结果表明，TR 远程拉曼光谱可能是一种有潜力的工具，可以在短距离和长距离内探测金星白天和夜间的表面矿物学。
