Strong isotope effect in the VUV photodissociation of HOD: A possible origin of D/H isotope heterogeneity in the solar nebula

被引：8

作者：

Luo, Zijie ^{[1
,2
]}

Zhao, Yarui ^{[2
]}

Chen, Zhichao ^{[2
]}

Chang, Yao ^{[2
]}

Zhang, Su-E ^{[2
]}

Wu, Yucheng ^{[2
]}

Yang, Jiayue ^{[2
]}

Cheng, Yi ^{[1
]}

Che, Li ^{[1
]}

Wu, Guorong ^{[2
]}

Xie, Daiqian ^{[3
]}

Yang, Xueming ^{[2
,4
]}

Yuan, Kaijun ^{[2
,5
]}

机构：

[1] Dalian Maritime Univ, Sch Sci, Dept Phys, 1 Linghai Rd, Dalian 116026, Liaoning, Peoples R China

[2] Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Mol React Dynam & Dalian Coherent L, 457 Zhongshan Rd, Dalian 116023, Peoples R China

[3] Nanjing Univ, Sch Chem & Chem Engn, Inst Theoret & Computat Chem, Key Lab Mesoscop Chem, Nanjing 210093, Peoples R China

[4] Southern Univ Sci & Technol, Coll Sci, Dept Chem, Shenzhen 518055, Peoples R China

[5] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

来源：

SCIENCE ADVANCES | 2021年 / 7卷 / 30期

基金：

中国国家自然科学基金;

关键词：

DISSOCIATION DYNAMICS; 121.6; NM; WATER MOLECULE; NOBLE-GASES; STATE; BOND; RATIO; H2O; (B)OVER-TILDE; ATMOSPHERES;

D O I：

10.1126/sciadv.abg7775

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

The deuterium versus hydrogen (D/H) isotopic ratios are important to understand the source of water on Earth and other terrestrial planets. However, the determinations of D/H ratios suggest a hydrogen isotopic diversity in the planetary objects of the solar system. Photochemistry has been suggested as one source of this isotope heterogeneity. Here, we have revealed the photodissociation features of the water isotopologue (HOD) at lambda = 120.8 to 121.7 nm. The results show different quantum state populations of OH and OD fragments from HOD photodissociation, suggesting strong isotope effect. The branching ratios of H + OD and D + OH channels display large isotopic fractionation, with ratios of 0.70 +/- 0.10 at 121.08 nm and 0.49 +/- 0.10 at 121.6 nm. Because water is abundant in the solar nebula, photodissociation of HOD should be an alternative source of the D/H isotope heterogeneity. This isotope effect must be considered in the photochemical models.

引用

页数：8

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