Fry Juliane L, Matthews Jamie, Lane Joseph R, Roehl Coleen M, Sinha Amitabha, Kjaergaard Henrik G, Wennberg Paul O
Arthur Amos Laboratory of Chemical Physics, California Institute of Technology, Pasadena, 91125, USA.
J Phys Chem A. 2006 Jun 8;110(22):7072-9. doi: 10.1021/jp0612127.
We report measurement and analysis of the photodissociation spectrum of hydroxymethyl hydroperoxide (HOCH(2)OOH) and its partially deuterated analogue, HOCD(2)OOH, in the OH-stretching region. Spectra are obtained by Fourier transform infrared spectroscopy in the 1nu(OH) and 2nu(OH) regions, and by laser induced fluorescence detection of the OH fragment produced from dissociation of HOCH(2)OOH initiated by excitation of the 4nu(OH) and 5nu(OH) overtone regions (action spectroscopy). A one-dimensional local-mode model of each OH chromophore is used with ab initio calculated OH-stretching potential energy and dipole moment curves at the coupled-cluster level of theory. Major features in the observed absorption and photodissociation spectra are explained by our local-mode model. In the 4nu(OH) region, explanation of the photodissocation spectrum requires a nonuniform quantum yield, which is estimated by assuming statistical energy distribution in the excited state. Based on the estimated dissociation threshold, overtone photodissociation is not expected to significantly influence the atmospheric lifetime of hydroxymethyl hydroperoxide.
我们报告了在羟基伸缩区域对羟甲基过氧化氢（HOCH₂OOH）及其部分氘代类似物HOCD₂OOH的光解离光谱进行的测量和分析。通过傅里叶变换红外光谱在1ν(OH)和2ν(OH)区域获得光谱，并通过激光诱导荧光检测由4ν(OH)和5ν(OH)泛音区域激发引发的HOCH₂OOH解离产生的OH片段（作用光谱）。每个OH发色团的一维局部模式模型与理论耦合簇水平上从头计算的OH伸缩势能和偶极矩曲线一起使用。我们的局部模式模型解释了观察到的吸收光谱和光解离光谱中的主要特征。在4ν(OH)区域，光解离光谱的解释需要非均匀量子产率，通过假设激发态中的统计能量分布来估计。基于估计的解离阈值，泛音光解离预计不会对羟甲基过氧化氢的大气寿命产生显著影响。
