Resonance Raman Intensity Analysis of ClNO2 Dissolved in Methanol

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• 作者：Marilena Trimithioti ; Sophia C. Hayes
• 刊名：The Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：January 17, 2013
• 年：2013
• 卷：117
• 期：2
• 页码：300-310
• 全文大小：401K
• 年卷期：v.117,no.2(January 17, 2013)
• ISSN：1520-5215

文摘

Halogens such as chlorine are converted from halides, including ClNO₂, to reactive radicals by UV solar radiation. These radicals can affect ozone production and destruction in the stratosphere. Recently, it became clear that halogen radicals can also play a significant role in the chemistry of the troposphere. The photochemistry of ClNO₂ has been the subject of several studies in the gas and solid state that demonstrated a clear phase-dependent reactivity. Here, we report our initial studies of nitryl chloride in solution. Resonance Raman (RR) spectra of ClNO₂ dissolved in methanol after excitation within the 1¹A₁鈥?¹A₁ absorption band (D band) in the region 200鈥?40 nm are presented. RR intensity along the NO symmetric stretch coordinate (v₁) at 1291 cm^鈥? is observed at all excitation wavelengths, whereas limited intensity corresponding to the transition of the N鈥揅l symmetric stretch (v₃) was only observed at 199.8 nm, whereas no intensity corresponding to the O鈥揘鈥揙 symmetric bend (v₂) was observed. Depolarization ratios and absolute resonance Raman cross sections for v₁ were obtained at several excitation wavelengths spanning the D band. Depolarization ratios were found to deviate significantly from 1/3, consistent with more than a single dipole-allowed electronic transition contributing to the scattering. RR intensity analysis (RRIA) reveals that two closely spaced excited electronic states contribute to the scattering, which are dissociative along the Cl鈥揘 coordinate. In this study the role the solvent environment plays in ClNO₂ state energetics and excited structural evolution along fundamental coordinates is discussed.