Department of Earth Science, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, United Kingdom.
J Phys Chem B. 2010 Dec 9;114(48):15753-8. doi: 10.1021/jp105020f. Epub 2010 Nov 10.
The infrared response of coronene (C(24)H(12)) under pressure and temperature conditions up to 10 GPa and 300 °C is examined in situ using a diamond anvil cell and synchrotron-source Fourier transform infrared (FTIR) spectroscopy. Coronene is a polycyclic aromatic hydrocarbon that is present in the interstellar medium and meteorites which may have contributed to the Earth's primordial carbon budget. It appears to undergo a reversible phase transition between 2 and 3.2 GPa at ambient temperature; new intramolecular bonds in the region 840-880 cm(-1) result from compression. We document the shift of spectral features to higher wavenumbers with increasing pressure but find this change suppressed by increased temperature. By investigating the stability of coronene over a range of naturally occurring conditions found in a range of environments, we assess the survival of the molecule through various terrestrial and extraterrestrial processes. Coronene has previously been shown to survive atmospheric entry during Earth accretion; this can now be extended to include survival through geological processes such as subduction and silicate melting of the rock cycle, opening the possibility of extraterrestrial coronene predating terrestrial accretion existing on Earth.
在高达 10 GPa 和 300°C 的压力和温度条件下，使用金刚石对顶砧和同步辐射傅里叶变换红外（FTIR）光谱原位研究了 coronene（C(24)H(12)）的红外响应。Coronene 是一种多环芳烃，存在于星际介质和陨石中，可能对地球原始碳预算有贡献。它似乎在环境温度下在 2 到 3.2 GPa 之间经历了一个可逆的相变；在 840-880 cm(-1) 区域新的分子内键是由压缩产生的。我们记录了随着压力的增加光谱特征向更高波数的移动，但发现这种变化被升高的温度抑制了。通过研究 coronene 在一系列环境中自然存在的条件范围内的稳定性，我们评估了该分子在各种地球和星际过程中的生存能力。Coronene 以前已经被证明在地球吸积过程中能够在大气进入时存活下来；现在可以将其扩展到包括通过俯冲和岩石循环的硅酸盐熔融等地质过程的存活，从而有可能存在先于地球吸积的外星 coronene 存在于地球上。
