title: Meteorite Impact-Induced Rapid NH3Production on Early Earth: Ab Initio Molecular Dynamics Simulation.
abstract: NH3is an essential molecule as a nitrogen source for prebiotic amino acid syntheses such as the Strecker reaction. Previous shock experiments demonstrated that meteorite impacts on ancient oceans would have provided a considerable amount of NH3from atmospheric N2and oceanic H2O through reduction by meteoritic iron. However, specific production mechanisms remain unclear, and impact velocities employed in the experiments were substantially lower than typical impact velocities of meteorites on the early Earth. Here, to investigate the issues from the atomistic viewpoint, we performed multi-scale shock technique-based ab initio molecular dynamics simulations. The results revealed a rapid production of NH3within several picoseconds after the shock, indicating that shocks with greater impact velocities would provide further increase in the yield of NH3. Meanwhile, the picosecond-order production makes one expect that the important nitrogen source precursors of amino acids were obtained immediately after the impact. It was also observed that the reduction of N2proceeded according to an associative mechanism, rather than a dissociative mechanism as in the Haber-Bosch process.
authors.affiliation: Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Shimamura
authors.affiliation: Department of Physics, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Shimojo
authors.affiliation: Collaboratory for Advanced Computing and Simulations, Department of Physics &Astronomy, Department of Computer Science, Department of Chemical Engineering &Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0242, USA.
authors.forename: Aiichiro
authors.initials: A
authors.lastname: Nakano
authors.affiliation: Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Tanaka
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D018534:Earth, Planet; D007501:Iron / Q000737:chemistry; D019110:Meteoroids; D056004:Molecular Dynamics Simulation; D009584:Nitrogen / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D000641:Ammonia; D007501:Iron; D009584:Nitrogen