Hu Y J, Fu H B, Bernstein E R
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
J Chem Phys. 2006 Oct 21;125(15):154305. doi: 10.1063/1.2357952.
A high sensitivity spectroscopy is employed to detect vibrational antiitions of ethanol neutrals and ions in a supersonic expansion. The infrared (IR) features located at 3682 and 3667 cm(-1) can be assigned to the OH stretch for the two neutral C(2)H(5)OH conformers, anti and gauche, respectively. Their overtone energies located at 7179 (anti) and 7141 (gauche) cm(-1) are also identified. The OH fundamental stretch for ethanol ions is redshifted around 210 cm(-1), while the CH stretch modes are unchanged for neutral and ionic C(2)H(5)OH at around 2900-3000 cm(-1). The charge on the ethanol ion is apparently localized on the oxygen atom. IR induced photodissociation spectroscopy is applied to the study of neutral and protonated ethanol clusters. Neutral and protonated ethanol cluster vibrations are observed. The CH modes are not perturbed by the clustering process. Neutral clusters display only hydrogen bonded OH features, while the protonated ionic clusters display both hydrogen bonded and non-hydrogen-bonded features. These spectroscopic results are analyzed to obtain qualitative structural information on neutral and ionic ethanol clusters.
采用高灵敏度光谱法检测超声速膨胀中乙醇中性分子和离子的振动跃迁。位于3682和3667 cm⁻¹处的红外（IR）特征峰可分别归属于两种中性C₂H₅OH构象异构体（反式和顺式）的OH伸缩振动。还识别出了它们位于7179（反式）和7141（顺式）cm⁻¹处的泛音能量。乙醇离子的OH基频伸缩振动红移约210 cm⁻¹，而对于中性和离子型C₂H₅OH，在2900 - 3000 cm⁻¹附近的CH伸缩振动模式不变。乙醇离子上的电荷显然定域在氧原子上。红外诱导光解离光谱法用于研究中性和质子化乙醇团簇。观察到了中性和质子化乙醇团簇的振动。CH模式不受团簇过程的干扰。中性团簇仅显示氢键OH特征峰，而质子化离子团簇则同时显示氢键和非氢键特征峰。对这些光谱结果进行分析以获得关于中性和离子型乙醇团簇的定性结构信息。
