Karthikeyan N, Joseph Prince J, Ramalingam S, Periandy S
Department of Physics, Parisutham Institute of Technology and Science, Thanjavur, Tamilnadu, India.
Department of Physics, Anna University, Bit Campus, Tiruchirappalli, Tamilnadu, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Apr 24;124:165-77. doi: 10.1016/j.saa.2013.12.105. Epub 2014 Jan 13.
In the present methodical study, FT-IR, FT-Raman and NMR spectra of the (2,4,5-Trichlorophenoxy) Acetic acid are recorded. The observed fundamental frequencies (IR and Raman) are assigned according to their distinctiveness region. The hybrid computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are tabulated. The impact of the presence of tri-chlorine atoms in phenyl structure of the compound is investigated. The vibrational sequence pattern of the molecule related to CH2COOH is analyzed. Moreover, (13)C NMR and (1)H NMR are calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra are simulated and the chemical shifts related to TMS are compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The Kubo gap of the present compound is calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand group. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. NLO properties related to Polarizability and hyperpolarizability are also discussed.
在本系统研究中，记录了（2,4,5-三氯苯氧基）乙酸的傅里叶变换红外光谱（FT-IR）、傅里叶变换拉曼光谱（FT-Raman）和核磁共振光谱（NMR）。根据其特征区域对观测到的基频（红外和拉曼）进行了归属。采用HF和DFT（B3LYP和B3PW91）方法，使用6-31++G(d,p)和6-311++G(d,p)基组进行了混合计算，并将相应结果制成表格。研究了化合物苯基结构中三氯原子的存在所产生的影响。分析了与CH2COOH相关的分子振动序列模式。此外，使用B3LYP方法和6-311++G(d,p)基组，通过规范无关原子轨道（GIAO）方法计算了(13)C NMR和(1)H NMR，并模拟了它们的光谱，比较了与四甲基硅烷（TMS）相关的化学位移。采用HF和DFT方法对电子和光学性质进行了研究，包括吸收波长、激发能、偶极矩和前线分子轨道能量。计算了本化合物与最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能量相关的久保能隙，证实了碱基和配体基团之间发生了电荷转移。除了前线分子轨道（FMO），还进行了分子静电势（MEP）计算。还讨论了与极化率和超极化率相关的非线性光学（NLO）性质。
