Ammonia: Did it have a Role in Chemical Evolution?
The possibility that biomolecules necessary for life were formed in a reducing atmosphere was first suggested by Oparin in his classic treatise on the origins of life (2). Urey calculated from equilibrium thermodynamic data that CH4 and NH3 were the predominant compounds of carbon and nitrogen in the atmosphere of the primitive Earth if a minimum of 10-3 atmosphere of H2 were present (3). Rasool and McGovern postulated, on the basis of an equilibrium model for the primitive Earth, that the exospheric temperature was between 500–1000°Kf, so that the rate of H2 loss was relatively slow (4,5). They calculated that, with this slow rate of loss, there would have been sufficient H2 to maintain NH3 in the primitive atmosphere for 108–109 years.
KeywordsQuantum Yield Chemical Evolution Order Rate Constant Effective Shield Rensselaer Polytechnic Institute
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Notes and References
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