2021 Fiscal Year Annual Research Report
Quantum Chemical Determination of the Complex Organic Molecules Formation in the Interstellar Medium
Publicly Offered Research
| Project Area | Next Generation Astrochemistry: Reconstruction of the Science Based on Fundamental Molecular Processes |
|---|
| Project/Area Number |
21H05416
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
Sameera W.M.C. 北海道大学, 低温科学研究所, 特任助教 (90791278)
|
|---|
| Project Period (FY) |
2021-09-10 – 2023-03-31
|
| Keywords | Radicals on ice surfaces / Binding energy / Reaction mechanisms / DFT / QM/MM / MC-AFIR |
|---|
| Outline of Annual Research Achievements |
To understand the formation of the complex organic molecules (COM), quantitative mechanistic details of the radical reactions on icy grains at very low temperatures are required. I use quantum chemical calculations to determine quantitative mechanistic details of the radical reactions on the interstellar ices. The present study calculated reaction mechanisms between CH3OH, an important molecule in the interstellar medium (ISM), and an OH radical on ices using the multi-component artificial force induced reaction (MC-AFIR) method. The artificial force of 100 kJ/mol was added between the OH and CH3OH on an ice cluster models. The MC-AFIR search gave a number of reaction paths, where I found two reaction mechanisms; OH + CH3OH -> CH2OH + H2O and OH + CH3OH ->CH3O + H2O. Both reaction mechanisms have very low reaction barriers. Thus, both reactions would occur on ices at low temperatures. Among the products of the reactions, formation of CH2OH is thermodynamically more stable than CH3O formation.
|
| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
One of the main objectives of the current project is to rationalize the reaction mechanism between OH and CH3OH on ices. I have already established the reaction mechanisms using a systematic reaction path search method, MC-AFIR; OH + CH3OH ->CH2OH + H2O and OH + CH3OH -> CH3O + H2O. Both reactions may be occurred on ices in the ISM. A manuscript is in preparation from the current research outcomes.
|
| Strategy for Future Research Activity |
The next step is to calculate reaction rates for the two mechanisms; OH + CH3OH ->CH2OH + H2O and OH + CH3OH -> CH3O + H2O. The transition state theory, including quantum tunnelling at low temperatures, will be used for this purpose. As the next step, another CH3OH molecule and a H2O molecule will be introduced, i.e., OH + 2CH3OH + H2O. Then the reaction mechanisms on ices will be determined from the MC-AFIR method. Finally, detailed reaction mechanisms for the formation of methyl formate, glycolaldehyde, methoxy methanol, and ethylene glycol will be rationalized.
|
-
-
-
-
-
-
-
-
-
-
[Book] Elsevier Publishing2022
Author(s)
W. M. C. Sameera, Y. Sumiya, B. B. Skjelstad, S. Maeda
Total Pages
Accepted
Publisher
Automated Mechanism Discovery, Comprehensive Computational Chemistry
-
