An experimental study of photochemistry for phosphine on interstellar silicate dust
| Project/Area Number |
21K13974
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 17010:Space and planetary sciences-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
NGUYEN THANH 北海道大学, 低温科学研究所, 博士研究員 (40846599)
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| Project Period (FY) |
2021-04-01 – 2022-03-31
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| Project Status |
Discontinued (Fiscal Year 2021)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2022: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2021: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
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| Keywords | Astrochemistry / Interstellar medium / Amorphous silicate / Photochemistry / Phosphine / Astrochemitry / Molecular cloud / Bare silicate dust |
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| Outline of Research at the Start |
Photochemistry of PH3 and PH3-containing ices (i.e., PH3/H2O, PH3/CO, and PH3/NH3) will be investigated by using UV photons on a Mg2SiO4 substrate at different temperatures. Photoproducts formed from photodissociation of PH3 and PH3-containing ices may react to form new P-bearing species such as P2H4, PN, PO, HPCO, HPO and/or H3PO4 on the Mg2SiO4 substrate. The decrease of PH3, PH3-containing ices, and the formation of new P-bearing molecules will be detected and recorded through using Fourier-transform infrared (FTIR) spectrometer and quadruple mass spectrometer (QMS), respectively.
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| Outline of Annual Research Achievements |
The purpose is to study the photochemistry of phosphine and PH3 containing ices on bare silicate dust at low temperatures (typically 10 K).
Firstly, I carried out experiments on the photochemical reactions of PH3 on amorphous forsterite (Mg2SiO4), which is expected to be dominant components of interstellar grains, at 10K. I obtained the missing PH3 on Mg2SiO4 at 10K by photodissociation after UV photolysis following reactions: PH3 + hv → PH2 + H; simultaneously, a small trace of P2H4 could be formed from PH2 + PH2 → P2H4 reaction. I also carried out another experiment of PH3 photolysis on water ice at 10 K to compare to the effective photodesorption of PH3 on Mg2SiO4. Based on the effective photodesorption of PH3, I may remark that the different effective photodesorption of PH3 on Mg2SiO4 and on water ice is due to the big different binding energy on different surfaces.
Secondly, I surveyed the photolysis of PH3/CO binary on Mg2SiO4. After photodissociation of PH3/CO binary on Mg2SiO4 in 2 hours, I got some products as HCO, H2CO, and HPCO. HCO and H2CO were formed from CO + H reaction; in there, H atoms were produced from the photodissociation of PH3. Furthermore, HPCO, which should be formed from PH + CO → HPCO reaction, has been detected. Additional, HPCO is a phosphorus containing analogues of isocyanic Acid which has been proposed to exit in interstellar space, but it has not been detected there. My experimental result, therefore, may contribute to study the complex phosphorus molecules on bare silicate dust.
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Report
(1 results)
Research Products
(3 results)
