Wen J S, Pinto J P, Yung Y L
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, USA.
J Geophys Res. 1989 Oct 20;94(D12):14957-70. doi: 10.1029/jd094id12p14957.
The role photochemical reactions in the early Earth's atmosphere played in the prebiotic synthesis of simple organic molecules was examined. We have extended an earlier calculation of formaldehyde production rates to more reduced carbon species, such as methanol, methane, and acetaldehyde. We have simulated the experimental results of Bar-Nun and Chang (1983) as an acid in the construction of our photochemical scheme and as a way of validating our model. Our results indicate that some fraction of CO2 and H2 present in the primitive atmosphere could have been converted to simple organic molecules. The exact amount is dependent on the partial pressure of CO2 and H2 in the atmosphere and on what assumptions are made concerning the shape of the absorption spectra of CO2 and H2O. In particular, the results are most sensitive to the presence or absence of absorption at wavelengths longward of 2000 angstroms. We also find that small quantities of CH4 could have been present in the prebiotic Earth's atmosphere as the result of the photoreduction of CO.
研究了光化学反应在早期地球大气中对简单有机分子的益生元合成所起的作用。我们已将甲醛生成速率的早期计算扩展到更还原的碳物种，如甲醇、甲烷和乙醛。在构建我们的光化学方案时，我们模拟了Bar-Nun和Chang（1983年）的实验结果，并将其作为验证我们模型的一种方式。我们的结果表明，原始大气中存在的一部分二氧化碳和氢气可能已转化为简单有机分子。确切数量取决于大气中二氧化碳和氢气的分压，以及对二氧化碳和水吸收光谱形状所做的假设。特别是，结果对2000埃以上波长处是否存在吸收最为敏感。我们还发现，由于一氧化碳的光还原作用，益生元地球大气中可能存在少量甲烷。
