Vibrational energy relaxation of aqueous azide ion confined in reverse micelles
Vibrational energy relaxation of aqueous azide ion confined in reverse micelles
复制标题
限制在反胶束中的含水叠氮化物离子的振动能量弛豫
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Owrutsky
中科院分区：
文献类型：
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作者：
Q. Zhong;A. Baronavski;J. Owrutsky
用超快红外光谱法测量了叠氮离子在非离子反胶束（RM）水池中的振动能量弛豫（VER）时间，其振动能量弛豫时间在2000 cm−1附近.通过调节水与表面活性剂的摩尔比ω=[H2O]/[表面活性剂]，在1-3 nm范围内改变水池半径。与本工作中测量的本体水的值（0.81±0.06 ps）相比，对于所研究的最小RM（ω=1），VER衰减时间约长3倍（2.5±0.2 ps），并且随着ω和RM尺寸的增加而变短，但没有达到所研究的最大ω时的本体值。先前已经报道了RM中叠氮化物振动带的溶剂位移[Langmuir 18，7401（2002）]，并且以与VER速率类似的方式，随着ω的增加，倾向于本体水值。叠氮离子在RM中的VER动力学的研究被用来研究溶剂化的限制效应，并探讨通过改变溶剂的浓度来连续修改溶质-溶剂相互作用的影响。
Vibrational energy relaxation (VER) times have been measured by ultrafast infrared spectroscopy near 2000 cm−1 for the antisymmetric stretching ν3 band of azide ion in water pools of nonionic reverse micelles (RM). The water pool radii were varied in the 1–3 nm range by adjusting the water-to-surfactant molar ratio, ω=[H2O]/[surfactant]. Compared to the value measured in this work for bulk water (0.81±0.06 ps), the VER decay times are about three times longer (2.5±0.2 ps) for the smallest RM studied (ω=1) and become shorter with increasing ω and RM size but do not reach the bulk value at the largest ω studied. Solvent shifts of the azide vibrational band in RMs have been previously reported [Langmuir 18, 7401 (2002)], and in a manner similar to the VER rates, tend toward the bulk water value with increasing ω. Studies of the VER dynamics of azide ion in RMs are used to investigate confinement effects on solvation and to explore the effects of continuously modifying the solute–solvent interaction by varyin...