Infrared spectroscopy of Li(+)(CH4)1Ar(n), n = 1-6, clusters.
Infrared spectroscopy of Li(+)(CH4)1Ar(n), n = 1-6, clusters.
复制标题
Li( )(CH4)1Ar(n)（n = 1-6）簇的红外光谱。
DOI：
--
复制
发表时间：
2011
影响因子：
2.9
通讯作者：
J. Lisy
中科院分区：
文献类型：
--
作者：
Oscar Rodríguez;J. Lisy
Li(+)(CH(4))(1)Ar(n), n = 1-6, 簇的红外预解离(IRPD) 光谱报告在2800 至3100 cm(-1) 的C-H 伸缩区域。 Li(+) 电场扰乱 CH(4)，提升其四面体对称性，并产生多种红外激活模式。观察到的带由完全对称振动模式 v(1) 和三重简并振动模式 v(3) 产生。相对于未受扰动的 CH(4) 值，每个频带均移至较低频率。随着氩原子数量的增加，C-H 红移变得不太明显，直到能带从 n = 5 到 n = 6 基本不变。对于 n = 6，观察到额外的振动特征，这表明存在额外的构象异构体。通过监测不同的光解离损失通道（三个Ar的损失或CH（4）的损失），一种构象异构体与CH（4）损失通道唯一相关，在2914和3017cm（-1）处有两个谱带，其值与中性CH（4）气相v（1）和v（3）频率几乎相同。通过支持从头计算，确定了两种构象异构体，其第一溶剂壳尺寸均为 6。主要构象异构体在第一壳层中具有CH(4)，而仅存在于CH(4)损失通道中的构象异构体在第一壳层中具有六个氩气，而CH(4)在第二壳层中。该构象异构体的能量比 MP2/aug-cc-pVDZ 水平的最小能量构象异构体高+11.89 kJ/mol。报道了 B3LYP/6-31+G* 级振动频率和 MP2/aug-cc-pVDZ 级单点结合能 D(e) (kJ/mol)，以支持对实验数据的解释。
Infrared predissociation (IRPD) spectra of Li(+)(CH(4))(1)Ar(n), n = 1-6, clusters are reported in the C-H stretching region from 2800 to 3100 cm(-1). The Li(+) electric field perturbs CH(4) lifting its tetrahedral symmetry and gives rise to multiple IR active modes. The observed bands arise from the totally symmetric vibrational mode, v(1), and the triple degenerate vibrational mode, v(3). Each band is shifted to lower frequency relative to the unperturbed CH(4) values. As the number of argon atoms is increased, the C-H red shift becomes less pronounced until the bands are essentially unchanged from n = 5 to n = 6. For n = 6, additional vibrational features were observed which suggested the presence of an additional conformer. By monitoring different photodissociation loss channels (loss of three Ar or loss of CH(4)), one conformer was uniquely associated with the CH(4) loss channel, with two bands at 2914 and 3017 cm(-1), values nearly identical to the neutral CH(4) gas-phase v(1) and v(3) frequencies. With supporting ab initio calculations, the two conformers were identified, both with a first solvent shell size of six. The major conformer had CH(4) in the first shell, while the conformer exclusively present in the CH(4) loss channel had six argons in the first shell and CH(4) in the second shell. This conformer is +11.89 kJ/mol higher in energy than the minimum energy conformer at the MP2/aug-cc-pVDZ level. B3LYP/6-31+G* level vibrational frequencies and MP2/aug-cc-pVDZ level single-point binding energies, D(e) (kJ/mol), are reported to support the interpretation of the experimental data.