Derro Erika L, Sechler Timothy D, Murray Craig, Lester Marsha I
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
J Chem Phys. 2008 Jun 28;128(24):244313. doi: 10.1063/1.2945872.
Hydrogen trioxy (HOOO) and its deuterated analog (DOOO) have been generated in a supersonic free-jet expansion through association of photolytically generated OH or OD and molecular oxygen. The radicals were detected using infrared action spectroscopy, a highly sensitive double resonance technique. Rotationally resolved spectra of combination bands of HOOO and DOOO comprising one quantum of OH or OD stretch (nu(1)) and one quantum of a lower frequency mode (nu(1)+nu(n) where n=3-6), including HDOO bend (nu(3)), OOO bend (nu(4)), central OO stretch (nu(5)), and HDOOO torsion (nu(6)), have been observed and assigned to the trans conformer. All but one of these bands are accompanied by unstructured features which are tentatively assigned to the corresponding vibration of the cis conformer. In total, five additional bands of HOOO and four of DOOO have been recorded and assigned. These data represent the first gas-phase observation of the low-frequency modes of HOOO and DOOO and they are found to differ significantly from previous matrix studies and theoretical predictions. Accurate knowledge of the vibrational frequencies is crucial in assessing thermochemical properties of HOOO and present possible means of detection in the atmosphere.
通过光解产生的OH或OD与分子氧缔合，在超声速自由射流膨胀中生成了三氧化氢（HOOO）及其氘代类似物（DOOO）。使用红外作用光谱法（一种高度灵敏的双共振技术）检测这些自由基。已观测到HOOO和DOOO的组合带的转动分辨光谱，这些组合带包含一个OH或OD伸缩量子（ν(1)）和一个低频模式量子（ν(1)+ν(n)，其中n = 3 - 6），包括HDOO弯曲（ν(3)）、OOO弯曲（ν(4)）、中心OO伸缩（ν(5)）和HDOOO扭转（ν(6)），并将其归属为反式构象体。除其中一个带外，所有这些带都伴有非结构化特征，暂将其归属为顺式构象体的相应振动。总共记录并归属了HOOO的另外五条带和DOOO的四条带。这些数据代表了对HOOO和DOOO低频模式的首次气相观测，发现它们与先前的基质研究和理论预测有显著差异。准确了解振动频率对于评估HOOO的热化学性质以及目前在大气中的可能检测手段至关重要。
