Matrix isolation spectroscopy and spectral simulations of isotopically substituted C60 molecules.
Matrix isolation spectroscopy and spectral simulations of isotopically substituted C60 molecules.
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同位素取代 C60 分子的基质隔离光谱和光谱模拟。
DOI：
10.1063/1.5134454
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发表时间：
2019
影响因子：
4.4
通讯作者：
M. Fajardo
中科院分区：
文献类型：
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作者：
Tomonari Wakabayashi;T. Momose;M. Fajardo
同位素富集（3.5%13 C）和贫化（0.5%13 C）富勒烯C60分子分离仲氢（pH 2）固体在低温下，并研究了高分辨率（0.01-0.1 cm-1）的红外（IR）吸收测量。光谱的天然同位素丰度（1.1%13 C）C60分子中分离的固体pH 2，正氘（oD 2），和Ne矩阵主机用于确定相对较小的光谱扰动，由于捕获环境。在Ih对称性中，观察到四个三重简并的IR活性T1 u模式的光谱特征，即T1 u（1）在529.77 cm-1，T1 u（2）在578.24 cm-1，T1 u（3）在1184.7 cm-1，T1 u（4）在1432 cm-1，被分配到的矩阵扰动振动模式光谱的一些13 Cn 12 C60-n同位素的叠加。新的分子轨道计算显示了13 C取代的对称性降低效应，即分裂的振动频率和修改的IR强度。红外光谱模式计算的328个不同的同位素13 Cn 12 C60-n至n = 3的使用满意地模拟所观察到的吸收功能。对于1432 cm-1的T1 u（4）模，观测到的分裂对13 C丰度不敏感，表明费米共振引起的光谱扰动。1545 cm-1处的弱吸收特征被分配给较低频率模式的组合。我们讨论的相对和绝对带强度的天体物理应用估计C60丰度的行星状星云。
Isotopically enriched (3.5% 13C) and depleted (0.5% 13C) fullerene C60 molecules are isolated in parahydrogen (pH2) solids at cryogenic temperatures and studied by high resolution (0.01-0.1 cm-1) infrared (IR) absorption measurements. Spectra of natural isotopic abundance (1.1% 13C) C60 molecules isolated in solid pH2, orthodeuterium (oD2), and Ne matrix hosts serve to identify the relatively minor spectral perturbations due to the trapping environments. Spectral features observed for the four IR-active T1u modes of threefold degeneracy in Ih symmetry, namely, T1u(1) at 529.77 cm-1, T1u(2) at 578.24 cm-1, T1u(3) at 1184.7 cm-1, and T1u(4) at 1432 cm-1, are assigned to the superpositions of matrix perturbed vibrational-mode spectra of a number of 13Cn 12C60-n isotopologues. New molecular orbital calculations show the symmetry lowering effects of 13C substitution, namely, split vibrational frequencies and modified IR intensities. IR spectral patterns calculated for the 328 distinct isotopomers of 13Cn 12C60-n up to n = 3 are used to satisfactorily simulate most of the observed absorption features. For the T1u(4) mode at 1432 cm-1, the observed splitting is insensitive to the 13C abundance, indicating spectral perturbations due to Fermi resonance. Weak absorption features at 1545 cm-1 are assigned to a combination of lower frequency modes. We discuss relative and absolute band strengths for the astrophysical application of estimating C60 abundances in planetary nebulae.