2021 Fiscal Year Annual Research Report
Multiscale modeling of radical diffusion and radical reactions on interstellar ices
| Project/Area Number |
19K03940
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| Research Institution | Hokkaido University |
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Principal Investigator |
Sameera W.M.C. 北海道大学, 低温科学研究所, 特任助教 (90791278)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | Radicals on ice surfaces / Binding energy / Reaction mechanisms / DFT / QM/MM |
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| Outline of Annual Research Achievements |
Radical processes on ices, specifically radical binding and radical reaction mechanisms, were studied using quantum chemical computations. A broader range of binding energies was found for CH3O (0.10-0.50 eV), where the interaction energy between the radical and ice determines the strength of the binding energy, while deformation of the radical or ice is negligible (J. Phy. Chem. A, 2021, 125, 1, 387-393). Computed reaction mechanisms of the radical reactions on ices, OCS + H and PH3 + D, rationalized the explained the experimentally observed products. Further, the reaction between OCS and H on ices yields CO and H2S as the major products and HC(O)SH as the minor product (Astrophys. J. 2021, 922, 146). The reaction between PH3 and D yields PD3, where step-wise dehydrogenation (Astrophys. J. 2021. 198, 73). In both reactions, the reaction barriers are relatively high. Therefore, quantum tunneling is critical for the reactions at low temperatures. These findings give quantitative insights into radical chemistry on ice surfaces in interstellar space.
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