Comparative vibrational spectroscopic studies, HOMO-LUMO, NBO analyses and thermodynamic functions of p-cresol and 2-methyl-p-cresol based on DFT calculations
Comparative vibrational spectroscopic studies, HOMO-LUMO, NBO analyses and thermodynamic functions of p-cresol and 2-methyl-p-cresol based on DFT calculations
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DOI：
10.1016/j.saa.2014.04.194
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发表时间：
2014-11-11
影响因子：
4.4
通讯作者：
Ilango, G.
中科院分区：
文献类型：
--
作者：
Balachandran, V.;Murugan, M.;Ilango, G.
本研究采用密度泛函理论（DFT）中的B3LYP/cc-pvdz和B3PW91/cc-pvdz，利用Becke三交换泛函和Lee Yang Paar相关泛函研究了对甲酚和2-甲氧基对甲酚的结构性质。记录了标题分子（固相）的傅里叶变换红外光谱和傅里叶变换拉曼光谱。分别用B3LYP/cc-pvdz和B3PW91/cc-pvdz基组计算了标题化合物的优化几何结构、谐波频率和各种热力学参数。利用上述基集测定电偶极矩、极化率α和超极化率β，研究了对甲酚和2-甲氧基对甲酚的非线性光学（NLO）行为。利用相同的基集，通过HOMO-LUMO分析，推导出了分子的电离势、电负性、化学势、亲电性等分子性质。报道了标题分子的红外和拉曼光谱的详细解释。在不同溶剂中测定了紫外光谱。利用时间相关密度泛函理论（TD-DFT）计算了能量和振子强度。计算出的HOMO和LUMO能量也证实了分子内发生了电荷转移。根据振动模态的势能分布（PED），用尺度量子力学（SQM）方法进行了完整的赋值。最后，本文还构建了标题分子的理论红外光谱、拉曼光谱和紫外光谱。(C) 2014 Elsevier B.V.版权所有
In the present study structural properties of p-cresol, and 2-methoxy-p-cresol have been studied by using B3LYP/cc-pvdz and B3PW91/cc-pvdz of Density Functional Theory (DFT) utilizing Becke three exchange functional and Lee Yang Paar correlation functional. The Fourier transform infrared and Fourier transform Raman spectra of title molecules were recorded (solid phase). Optimized geometry, harmonic vibrational frequencies and various thermodynamic parameters of the title compounds were calculated with B3LYP/cc-pvdz, and B3PW91/cc-pvdz basis sets. Non-linear optical (NLO) behavior of the p-cresol and 2-methoxy-p-cresol were investigated by determining of electric dipole moment, polarizability alpha, and hyperpolarizability beta using the above mentioned basis sets. The molecular properties such as ionization potential, electronegativity, chemical potential, electrophilicity have been deduced from HOMO-LUMO analysis employing the same basis sets. A detailed interpretation of the infrared and Raman spectra of title molecules were reported. UV spectrum was measured in different solvent. The energy and oscillator strength are calculated by Time Dependant Density Functional Theory (TD-DFT) results. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. The complete assignments were performed on the basis of the potential energy distribution (PED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method. Finally the theoretical FT-IR, FT-Raman, and UV spectra of the title molecules have also been constructed. (C) 2014 Elsevier B.V. All rights reserved.