Experimental test of self-shielding in vacuum ultraviolet photodissociation of CO

被引：68

作者：

Chakraborty, Subrata ^{[1
]}

Ahmed, Musahid ^{[2
]}

Jackson, Teresa L. ^{[1
]}

Thiemens, Mark H. ^{[1
]}

机构：

[1] Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA

[2] Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA

来源：

SCIENCE | 2008年 / 321卷 / 5894期

关键词：

D O I：

10.1126/science.1159178

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：

Self- shielding of carbon monoxide ( CO) within the nebular disk has been proposed as the source of isotopically anomalous oxygen in the solar reservoir and the source of meteoritic oxygen isotopic compositions. A series of CO photodissociation experiments at the Advanced Light Source show that vacuum ultraviolet ( VUV) photodissociation of CO produces large wavelength- dependent isotopic fractionation. An anomalously enriched atomic oxygen reservoir can thus be generated through CO photodissociation without self- shielding. In the presence of optical self- shielding of VUV light, the fractionation associated with CO dissociation dominates over self- shielding. These results indicate the potential role of photochemistry in early solar system formation and may help in the understanding of oxygen isotopic variations in Genesis solar- wind samples.

引用

页码：1328 / 1331

页数：4

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