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An experimental study of photochemistry for phosphine on interstellar silicate dust

星际硅酸盐尘埃中磷化氢的光化学实验研究

基本信息

批准号：
21K13974
负责人：
NGUYEN THANH
金额：
$ 3万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Early-Career Scientists
财政年份：
2021
资助国家：
日本
起止时间：
2021-04-01 至 2022-03-31
项目状态：
已结题

项目摘要

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.

目的是研究低温（通常为10 K）下裸硅酸盐粉尘上磷化氢和含冰PH3的光化学反应。首先，我在10K下进行了PH3在非晶态forsterite （Mg2SiO4）上的光化学反应实验，预计这将是星际颗粒的主要成分。在10K条件下，通过紫外光解，光解得到Mg2SiO4上缺失的PH3: PH3 + hv→PH2 + H；同时，PH2 + PH2→P2H4反应可生成少量P2H4。我还进行了另一项实验，在10 K条件下对水冰进行PH3光解实验，比较了Mg2SiO4对PH3的有效光解吸。根据PH3的有效光解吸，我可以指出，PH3在Mg2SiO4和水冰上的有效光解吸不同是由于不同表面上的结合能差异很大。其次，研究了PH3/CO二元在Mg2SiO4上的光解反应。PH3/CO二元在Mg2SiO4上光解2小时，得到HCO， H2CO， HPCO等产物。由CO + H反应生成HCO和H2CO；在那里，氢原子是由PH3的光解作用产生的。此外，还发现了PH + CO→HPCO反应生成的HPCO。此外，HPCO是一种含磷的异氰酸类似物，有人提出它会在星际空间中存在，但在那里还没有被检测到。因此，我的实验结果可能有助于研究裸露硅酸盐粉尘上的复杂磷分子。