检索结果-南通市图书馆

dissociation pathway Analysis of Thymine under Low Energy VUV Photon Excitation

Chinese Journal of Chemical Physics 2011年第3期24卷 275-283,I0003页

作者：李少波郭会军张李东齐飞中国科学技术大学国家同步辐射实验室合肥230029 合肥学院化学与材料工程系合肥230022

Photon-induced dissociation pathways of thymine are investigated with vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. The photoionization mass spectra of thymine at different photon energy are measured and presented. By selecting suitable photon energy, exclusively molecular ion m/z=126 is obtained. At photon energy of 12.0 eV, the major ionic fragments at m/z=98, 97, 84, 83, 70, and 55 are obtained, which are assigned to C4H6N2O＋, C4H5N2O＋, C3H4N2O＋（or C4H6NO＋）, C4H5NO＋, C2NO2＋, and C3H5N＋, respectively. With help of theoretical calculations, the detailed dissociation pathways of thymine at low energy are well established.

关键词： Thymine dissociation pathway VUV photoionization Mass spectrometry Theoretical calculation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photofragmentation of Isoleucine by Vacuum Ultraviolet Photoionization

引用

Chinese Journal of Chemical Physics 2012年第4期25卷 379-388,I0003页

作者：谢阳曹兰兰张强陈军储根柏赵玉杰单晓斌刘付轶盛六四中国科学技术大学国家同步辐射实验室核科学技术学院合肥230029

Vacuum ultraviolet photon-induced ionization and dissociation of isoleucine are investi- gated with synchrotron radiation photoionization mass spectroscopy and theoretical cal- culations. The main fragment ions at m/z=86, 75, 74, 69, 57, 46, 45, 44, 41, 30, 28, and 18 from isoleucine are observed in the mass spectrum at the photon energy of 13 eV. From the photoionization efficiency curves, appearance energies for the principal fragment ions CsH12N＋（rn/z=86）, C2H5NO2＋（m/z=75）, C5H9＋（rn/z=-69）, C4H9＋（m/z=57）, and CH4N＋（m/z=30） are determined to be 8.844-0.07, 9.254-0.06, 10.20-4-0.12, 9.254-0.10, and 11.05＋0.07 eV, respectively, and possible formation pathways are established in detail by the calculations at the B3LYP/6-31＋＋G（d, p） levels. These proposed channels include simple bond cleavage reactions as well as reactions involving intermediates and transition structures. The experimental and computational appearance energies or barriers are in good agreement.

关键词： Synchrotron radiation Vacuum ultraviolet Photoionization mass spectroscopy Isoleucine dissociation pathway

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

VUV Photoionization and dissociation of Tyramine and Dopamine： the Joint Experimental and Theoretical Studies

引用

Chinese Journal of Chemical Physics 2012年第1期25卷 11-18,I0003页

作者：郭会军叶莉莉贾良元张李东齐飞中国科学技术大学国家同步辐射实验室合肥230029

Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only molecular ions are measured by virtue of nearthreshold photoionization. While increasing photon energy to 11.7 eV or more, four distinct fragment ions are obtained for tyramine and dopamine, respectively. Besides, the ionization energies of tyramine and dopamine are determined to be 7.984-0.05 and 7.674-0.05 eV by measuring the photoionization efficiency curves of corresponding molecular ions. With help of density function theory calculations, the detailed fragmentation pathways are established as well. These two molecular cations have similar aminoethyl group elimination pathways, CTHsO2＋（m/z=124） and C7H8O＋（m/z=108） are supposed to be generated by the McLafferty rearrangement via γ-hydrogen （7-H） shift inducing β-fission. And CH2NH2＋ is proposed to derive from the direct fission of C7-C8 bond. Besides, the McLafferty rearrangement and the C7-C8 bond fission are validated to be dominant dissociation pathways for tyramine and dopamine cations.

关键词： Tyramine Dopamine VUV photoionization Mass spectrometry Ionization energy dissociation pathway

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：