Derro Erika L, Sechler Timothy D, Murray Craig, Lester Marsha I
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
J Phys Chem A. 2008 Oct 2;112(39):9269-76. doi: 10.1021/jp801232a. Epub 2008 May 29.
The DOOO radical has been produced by three-body association between OD and O2 in a supersonic free-jet expansion and investigated using action spectroscopy, an IR-UV double-resonance technique. Partially rotationally structured bands observed at 2635.06 and 5182.42 cm(-1) are assigned to the OD stretch fundamental (nu(OD)) and overtone (2nu(OD)), respectively, of the trans-DOOO radical. Unstructured bands observed in both spectral regions are assigned to cis-DOOO. Nascent OD X(2)Pi product state distributions following vibrational predissociation appear to be nearly statistical with respect to the degree of rotational excitation, but display a marked propensity for Pi(A') Lambda-doublets, which is interpreted as a signature of a planar dissociation. The energetically highest open OD X(2)Pi product channel implies an upper limit dissociation energy D0 < or = 1856 cm(-1) or 5.31 kcal mol(-1). This value allows refinement of the upper limit D0 of the atmospherically important HOOO isotopomer, suggesting that it is marginally less stable than previously thought.
DOOO自由基是通过超声速自由射流膨胀中OD与O₂的三体缔合产生的，并使用红外-紫外双共振技术——作用光谱法进行了研究。在2635.06和5182.42 cm⁻¹处观察到的部分具有转动结构的谱带分别归属为反式DOOO自由基的OD伸缩基频（ν(OD)）和倍频（2ν(OD)）。在两个光谱区域观察到的无结构谱带归属为顺式DOOO。振动预解离后新生的OD X²Π产物态分布在转动激发程度方面似乎接近统计分布，但对Π(A') Λ-双重态表现出明显的倾向，这被解释为平面解离的特征。能量上最高的开放OD X²Π产物通道意味着解离能上限D₀ ≤ 1856 cm⁻¹或5.31 kcal mol⁻¹。该值有助于完善大气中重要的HOOO同位素异构体的解离能上限D₀，表明其稳定性略低于先前的认识。
