Rueda David, Boyarkin Oleg V, Rizzo Thomas R, Chirokolava Andrei, Perry David S
Laboratoire de Chimie Physique Moléculaire, EPFL, Station-6, CH-1015 Lausanne, Switzerland.
J Chem Phys. 2005 Jan 22;122(4):44314. doi: 10.1063/1.1833353.
Spectra of jet-cooled methanol in the overtone and combination region from 5000 to 14 000 cm(-1) have been obtained by means of infrared laser-assisted photofragment spectroscopy. Many of the observed features are assigned to combination bands of the type nnu(1)+nu(6), nnu(1)+nu(8), and nnu(1)+nu(6)+nu(8) (n=1,2,3), where nu(1) is the OH stretch, nu(6) is the OH bend, and nu(8) is the CO stretch. These bands show sharp torsion-rotation structure with features as narrow as 0.1 cm(-1). We also observe CH stretch overtones that are weaker than the OH containing combination bands and lack distinct torsion-rotation structure above v(CH)=2. The extent of observed structure on these bands allows us to place limits on the intramolecular vibrational energy redistribution decay rates in the upper vibrational states. We report a global fit of the observed band centers to a simple expression involving low-order anharmonicity constants.
通过红外激光辅助光碎片光谱法获得了喷射冷却甲醇在5000至14000 cm⁻¹泛音和组合区域的光谱。许多观测到的特征被归属于nν₁+ν₆、nν₁+ν₈和nν₁+ν₆+ν₈（n = 1,2,3）类型的组合带，其中ν₁是OH伸缩振动，ν₆是OH弯曲振动，ν₈是CO伸缩振动。这些谱带显示出尖锐的扭转-转动结构，特征宽度窄至0.1 cm⁻¹。我们还观测到了CH伸缩泛音，其强度比含OH的组合带弱，并且在v(CH)=2以上缺乏明显的扭转-转动结构。这些谱带上观测到的结构程度使我们能够对高振动态下分子内振动能量重新分布的衰减率进行限制。我们报告了对观测到的谱带中心进行全局拟合，得到一个涉及低阶非谐常数的简单表达式。
