Suvitha A, Periandy S, Govindarajan M, Gayathri P
Periyar Maniyammai University, Vallam, Thanjavur, India; St. Francies College, Bangalore, India.
Department of Physics, Tagore Arts College, Puducherry, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Mar 5;138:900-12. doi: 10.1016/j.saa.2014.10.031. Epub 2014 Nov 4.
In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4000cm(-1)and 50-4000cm(-1), respectively, for 2,2,4-Trimethyl Pentane, TMP (C8H18) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and geometrical parameter calculations based on Hartree Fock (HF) and density functional theory (DFT) method with 6-311++G(d,p) basis set. The scaled B3LYP/6-311++G(d,p) results shows the best agreement with the experimental values over the other method. The calculated HOMO and LUMO energies shows that charge transfer within the molecule. The physical reactions of single bond hydrocarbon TMP were investigated. The results of the calculations were applied to simulate spectra of the title compound, which shows the excellent agreement with observed spectra. Besides, Mulliken atomic charges, UV, frontier molecular orbital (FMO), MEP, NLO activity, Natural Bond-Orbital (NBO) analysis, NMR and thermodynamic properties of title molecule were also performed.
在这项工作中，分别在100 - 4000cm⁻¹和50 - 4000cm⁻¹范围内，使用拉曼光谱和红外光谱对2,2,4 - 三甲基戊烷（TMP，C₈H₁₈）分子进行了振动光谱分析。借助基于Hartree Fock（HF）和密度泛函理论（DFT）方法、采用6 - 311++G(d,p)基组的结构优化和几何参数计算，对分子结构、基本振动频率和振动带强度进行了解释。与其他方法相比，缩放后的B3LYP/6 - 311++G(d,p)结果与实验值显示出最佳的一致性。计算得到的最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能量表明分子内存在电荷转移。研究了单键烃TMP的物理反应。计算结果被用于模拟标题化合物的光谱，其与观测光谱显示出极好的一致性。此外，还进行了Mulliken原子电荷、紫外光谱、前沿分子轨道（FMO）、分子静电势（MEP）、非线性光学（NLO）活性、自然键轨道（NBO）分析、核磁共振（NMR）以及标题分子的热力学性质研究。
