Solvent Dependence of Electronic Relaxation in All-trans Retinal Studied by One- and Two-Photon Induced Transient Absorption
Solvent Dependence of Electronic Relaxation in All-trans Retinal Studied by One- and Two-Photon Induced Transient Absorption
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通过一光子和二光子诱导瞬态吸收研究全反式视网膜中电子弛豫的溶剂依赖性
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发表时间：
2001
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通讯作者：
Carey K. Johnson
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作者：
E. Larson;and Sarah J. Pyszczynski;Carey K. Johnson
单光子和双光子激发的超快瞬态吸收测量报告的极性，非极性和氢键溶剂中的全反式视黄醛。一个比较的响应以下的一个和双光子激发允许分配所观察到的衰变的1Bu+样和1Ag-样激发态。在极性，氢键溶剂乙醇中，单光子激发后的瞬态吸收的变化主要由2-ps的响应中观察到的瞬态吸收的衰减和受激发射的衰减中观察到的区域从600至750 nm。由于强受激发射增益，这种响应可以归因于强光学允许的“1Bu+”状态的衰变。在乙醇中双光子激发全反式视黄醛时，也出现了200 − 300 fs的衰变分量，并被认为是具有大双光子截面的"1Ag-"态的衰变。相比之下，对于己烷中的全反式视黄醛，200 − 300 fs和2-ps衰减分量都是可见的。
One- and two-photon excited ultrafast transient absorption measurements are reported for all-trans retinal in polar, nonpolar, and hydrogen-bonding solvents. A comparison of the response following one- and two-photon excitation allows assignment of the observed decays to the 1Bu+-like and 1Ag--like excited states. In the polar, hydrogen-bonding solvent ethanol, the transient absorption changes following one-photon excitation are dominated by a 2-ps response observed both in the decay of transient absorption and in the decay of stimulated emission observed in the region from 600 to 750 nm. Because of the strong stimulated emission gain, this response can be assigned to decay of the strongly optically allowed “1Bu+” state. With two-photon excitation of all-trans retinal in ethanol, a 200−300 fs decay component appears as well and is assigned to decay of the “1Ag-” state, which has a large two-photon cross section. In contrast, for all-trans retinal in hexane, both 200−300 fs and 2-ps decay components are ob...