Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution

	Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution
	Yang, Chunfan 1; Su, Hongmei 1; Sun, Xuezhong 2; George, Michael W.2
刊名	journal of chemical physics
	2012-05-28
卷号	136 期号:20
英文摘要	time-resolved infrared (tr-ir) absorption spectroscopy in both the femtosecond and nanosecond time domain has been applied to examine the photolysis of benzoic acid in acetonitrile solution following either 267 nm or 193 nm excitation. by combining the ultrafast and nanosecond tr-ir measurements, both the excited states and the photofragments have been detected and key mechanistic insights were obtained. we show that the solvent interaction modifies the excited state relaxation pathways and thus the population dynamics, leading to different photolysis behavior in solution from that observed in the gas phase. vibrational energy transfer to solvents dissipates excitation energy efficiently, suppressing the photodissociation and depopulating the excited s-2 or s-3 state molecules to the lowest t-1 state with a rate of similar to 2.5 ps after a delayed onset of similar to 3.7 ps. photolysis of benzoic acid using 267 nm excitation is dominated by the formation of the t-1 excited state and no photofragments could be detected. the results from tr-ir experiments using higher energy of 193 nm indicate that photodissociation proceeds more rapidly than the vibrational energy transfer to solvents and c-c bond fission becomes the dominant relaxation pathway in these experiments as featured by the prominent observation of the cooh photofragments and negligible yield of the t-1 excited state. the measured ultrafast formation of t-1 excited state supports the existence of the surface intersections of s-2/s-1, s-2/t-2, and s-1/t-1/t-2, and the large t-1 quantum yield of similar to 0.65 indicates the importance of the excited state depopulation to triplet manifold as the key factor affecting the photophysical and photochemical behavior of the monomeric benzoic acid. (c) 2012 american institute of physics. [http://dx.doi.org/10.1063/1.4722084]
WOS标题词	science & technology ; physical sciences
类目[WOS]	physics, atomic, molecular & chemical
研究领域[WOS]	physics
关键词[WOS]	acetic-acid ; infrared-spectra ; 193 nm ; monomer ; spectroscopy ; dynamics ; channel ; dissociation ; selectivity ; matrix
收录类别	SCI
语种	英语
WOS记录号	WOS:000304818400039
公开日期	2015-11-17
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/143053]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
作者单位	1.Chinese Acad Sci, BNLMS, State Key Lab Mol React Dynam, Inst Chem, Beijing 100190, Peoples R China 2.Univ Nottingham, Sch Chem, University Pk NG7 2RD, England
推荐引用方式 GB/T 7714	Yang, Chunfan,Su, Hongmei,Sun, Xuezhong,et al. Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution[J]. journal of chemical physics,2012,136(20).
APA	Yang, Chunfan,Su, Hongmei,Sun, Xuezhong,&George, Michael W..(2012).Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution.journal of chemical physics,136(20).
MLA	Yang, Chunfan,et al."Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution".journal of chemical physics 136.20(2012).