摘要
本文首次结合理论计算与瞬态吸收光谱,阐明了典型的半花菁类化合物Hemicy和Dhemicy的紫外光防护动力学机理.理论和实验证明,Hemicy和Dhemicy在UVC、UVB和UVA区域都有很强的吸收能力.Hemicy和Dhemicy吸收能量后跃迁到激发态Hemicy和Dhemicy在S_(1)态和S_(0)态势能曲线的圆锥交点处,经历从S_(1)态到S_(0)态的非绝热弛豫和顺式反异构化光物理过程.瞬态吸收光谱表明反式-顺式光异构化过程将在几皮秒内发生.因此,通过非绝热反式-顺式光异构化过程快速地弛豫掉Hemicy和Dhemicy吸收的能量.
In this work,we rstly elucidated the ultra-violet light protection dynamics mechanism of the typical hemicyanines,i.e.Hemicy and DHemicy,by combining the theoretical cal-culation method and the transient absorp-tion spectra.It is theoretically and exper-imentally demonstrated that both Hemicy and DHemicy have strong absorption in UVC(200280 nm),UVB(280300 nm),and UVA(320400 nm)regions.More-over,after absorbing energy,Hemicy and DHemicy can jump into the excited states.Subsequently,Hemicy and DHemicy relax to S_(0)states from S_(1)states rapidly by the non-adiabatic transition at the conical intersection point between the potential energy curves of S_(1)and S_(0)states,and are accompanied by the trans-cis photoisomerism.The transient absorption spectra show that trans-cis photoisomerization occur within a few picoseconds.Thus,the ultraviolet energy absorbed by Hemicy and DHemicy could be relaxed ultrafastly by the non-adiabatic trans-cis photoisomerization processes.
作者
张明水
楚亚
吴子博
郭玉荣
史亚男
王朝
王孟琪
钟瑛倩
张皓月
王雅楠
王俊
赵广久
Ming-shui Zhang;Ya Chu;Zibo Wu;Yu-rong Guo;Ya-nan Shi;Chao Wang;Meng-qi Wang;Ying-qian Zhong;Hao-yue Zhang;Ya-nan Wang;Jun Wang;Guang-jiu Zhao(Tianjin Key Laboratory of Molecular Optoelectronic Sciences,Department of Chemistry,School of Science,Tianjin University,Tianjin 300354,China;College of Chemistry and Chemical Engineering,Northeast Petroleum University,Daqing 163318,China)
基金
This work was supported by the National Natural Science Foundation of China(No.21873068,No.21573229 and No.21422309).
关键词
半花菁
紫外光吸收剂
势能面
非绝热
顺反式光异构化
Hemicyanine
Ultraviolet photoabsorber
Potential energy surface
Non-adiabatic
Trans-cis photoisomerization
