Department of Applied Physics, Sri Venkateswara College of Engineering, Sriperumbudur 602 105, Tamil Nadu, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Aug;112:169-81. doi: 10.1016/j.saa.2013.04.024. Epub 2013 Apr 11.
The FT-IR and FT-Raman spectra of ethyl 4-aminobenzoate (EAB) in the solid phase were recorded. The fundamental vibrational wavenumbers, intensities of vibrational bands and the optimized geometrical parameters of the compound were evaluated using DFT (B3LYP) method with 6-311++G(d,p) basis set. The stable geometry of the compound was determined from the potential energy surface scan. Complete vibrational assignments and Natural Bond Orbital (NBO) analysis for the title compound were carried out. The assignments of the vibrational spectra were carried out with the help of normal co-ordinate analysis (NCA) following the Scaled Quantum Mechanical Force Field (SQMFF) methodology. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. UV-visible spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies were performed by time-dependent DFT (TD-DFT) approach. Mulliken population analysis on atomic charges were also calculated. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed.
本文记录了乙基 4-氨基苯甲酸酯（EAB）在固相中的傅立叶变换红外（FT-IR）和傅立叶变换拉曼（FT-Raman）光谱。采用 B3LYP 方法和 6-311++G（d，p）基组，评估了化合物的基本振动波数、振动带的强度和优化的几何参数。通过势能面扫描确定了化合物的稳定几何形状。对标题化合物进行了完整的振动归属和自然键轨道（NBO）分析。振动光谱的分配是在遵循标度量子力学力场（SQMFF）方法的正则坐标分析（NCA）的帮助下进行的。利用总（TDOS）、部分（PDOS）和重叠人口（OPDOS）态密度研究了分子轨道贡献。记录了化合物的紫外-可见光谱，并通过时间相关的密度泛函理论（TD-DFT）方法进行了电子性质，如 HOMO 和 LUMO 能量的计算。还计算了原子电荷的 Mulliken 布居分析。此外，还进行了分子静电势（MEP）和热力学性质的计算。
