One- and Two-Photon Absorption of a Spiropyran鈥揗erocyanine System: Experimental and Theoretical Studies

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• 作者：Katarzyna Matczyszyn ; Joanna Olesiak-Banska ; Keitaro Nakatani ; Pei Yu ; N. Arul Murugan ; Robert Zale艣ny ; Agnieszka Roztoczy艅ska ; Joanna Bednarska ; Wojciech Bartkowiak ; Jacob Kongsted ; Hans 脜gren ; Marek Samo膰
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：January 29, 2015
• 年：2015
• 卷：119
• 期：4
• 页码：1515-1522
• 全文大小：380K
• ISSN：1520-5207

文摘

We report on the nonlinear optical properties measurements and quantum-chemical calculations of a well-known photochromic system consisting of spiropyran and the merocyanine photoproduct. The study of nonlinear absorption and refraction properties of the molecules dissolved in chloroform were performed with the Z-scan technique, using femtosecond pulses in a wide range of wavelengths. Maxima in the two-photon absorption spectrum at 700 and 1050 nm were found for the merocyanine form, and the corresponding two-photon absorption cross section is 80 GM and 20 GM, respectively. The latter feature does not vanish completely in the nonlinear spectrum of the spiropyran form, possibly because of the existence of some photoconversion caused by the laser beam during the measurements. A nonlinear absorption peak at 900 nm is found in the spiropyran form with an effective cross section of about 20 GM; it is likely due to three-photon absorption or to absorption by some intermediate species. The experimental data are supported by calculations performed with the use of a hybrid quantum mechanics鈥搈olecular mechanics approach.