Thermal Lensing in a Supercritical Water Medium

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• 作者：Rene G. Rodriguez ; Stephen P. Mezyk ; Charlynn Stewart ; Harry W. Rollins ; Bruce J. Mincher ; Robert V. Fox ; BarJean Phillips ; Richard Brey
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：January 25, 2007
• 年：2007
• 卷：111
• 期：3
• 页码：468 - 471
• 全文大小：96K
• 年卷期：v.111,no.3(January 25, 2007)
• ISSN：1520-5215

文摘

A pulsed, two-beam, thermal lensing experiment was performed to determine the concentration of aqueoussolutes above the critical point of water. Despite a very significant mirage effect due to thermal gradients inthe cell and absorption by water itself, the thermal lensing signal strength for aqueous benzoic acid insupercritical water was found to be linear with concentration in the sub-millimolar range. Although thermallensing experiments in aqueous media are notoriously insensitive, the sharp density gradient near the criticalpoint considerably improves the signal intensity. In this study a short-pulse pump 266 nm YAG laser andcontinuous low-power probe Ar ion beam were both focused into a supercritical water cell, giving a lensingsignal whose strength could be maximized by changing the overlap of the two beams.