Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy

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	Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy
	Hua, XinZhong; Hua, LinQiang; Liu, XiaoJun
刊名	JOURNAL OF PHYSICAL CHEMISTRY A
	2015-12-31
卷号	119 期号:52 页码:12985-12989
英文摘要	The excited-state dynamics of 6-azauracil in different solvents have been studied using femtosecond transient absorption spectroscopy. The molecule is populated to the S-2 state with a pump pulse at 264 nm. Broad-band white light continuum which covers from 320 to 600 nm is used as the probe. With a global fitting analysis of the measured transient spectra, three decay time constants, i.e., <0.3, 5.2 +/- 0.1, and >1000 ps, are directly obtained in the solvent of acetonitrile. These newly observed lifetime constants are important in clarifying its decay dynamics as well as in providing a criterion for the ultrafast dynamics simulations in 6-azauracil using quantum chemical theories. In combination with previous theoretical works, the main decay channel is proposed: the initially populated S-2 decays to S-1 through internal conversion in <0.3 ps, followed by an intersystem crossing from S-1 to T-1 in 5.2 +/- 0.1 ps. The >1000 ps component is due to the decay of the T-1 state. A comparison of the excited-state dynamics in different solvents reveals that the decay from S, to T-1 shows a clear dependence on the polarity of the solvents. With higher polarity, the S-1 excited state decays faster. This observation is in line with the prediction by Etinski et al. [Phys. Chem. Chem. Phys. 2010, 12, 15665-15671], where a blue-shift of the T-1 state potential energy surface leading to an increase of the intersystem crossing rate was proposed. With the new information obtained in the present measurement, a clearer picture of the decay dynamics of 6-azauracil on the S-2 excited state is provided.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Chemistry, Physical ; Physics, Atomic, Molecular & Chemical
研究领域[WOS]	Chemistry ; Physics
关键词[WOS]	FLUORESCENCE UP-CONVERSION ; ELECTRONIC GROUND-STATE ; RELAXATION MECHANISMS ; URACIL DERIVATIVES ; AQUEOUS-SOLUTION ; THYMINE ; ACETONITRILE ; PATHWAYS ; DECAY ; BASES
收录类别	SCI
语种	英语
WOS记录号	WOS:000367705400009
公开日期	2016-05-09
内容类型	期刊论文
源URL	[http://ir.wipm.ac.cn/handle/112942/9144]
专题	武汉物理与数学研究所_原子分子光物理研究部
作者单位	Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China
推荐引用方式 GB/T 7714	Hua, XinZhong,Hua, LinQiang,Liu, XiaoJun. Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy[J]. JOURNAL OF PHYSICAL CHEMISTRY A,2015,119(52):12985-12989.
APA	Hua, XinZhong,Hua, LinQiang,&Liu, XiaoJun.(2015).Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy.JOURNAL OF PHYSICAL CHEMISTRY A,119(52),12985-12989.
MLA	Hua, XinZhong,et al."Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy".JOURNAL OF PHYSICAL CHEMISTRY A 119.52(2015):12985-12989.