Muthu S, Elamuruguporchelvi E, Varghese Anitha
Department of Physics, Sri Venkateswara College of Engg, Sriperumbudur 602105, Tamil Nadu, India.
Department of Physics, Kanchi Pallavan Engineering College, Kanchipuram 631502, Tamil Nadu, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Mar 5;138:743-52. doi: 10.1016/j.saa.2014.11.035. Epub 2014 Dec 4.
The solid phase FTIR and FT-Raman spectra of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate (25N2LCPA) have been recorded 450-4000cm(-1) and 100-4000cm(-1) respectively. The normal coordinate analysis was carried out to confirm the precision of the assignments. DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies and IR intensities. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31+G(d,p) basis set. The detailed interpretation of the vibrational spectra has been carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The Vibrational frequencies are calculated in the above method and are compared with experimental frequencies which yield good agreement between observed and calculated frequencies. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. In addition, Frontiers molecular orbital and molecular electrostatic potential were computed by using Density Functional Theory (DFT) B3LYP/6-31+G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule.
已分别在450 - 4000cm⁻¹和100 - 4000cm⁻¹范围内记录了2 - [(5 - 硝基 - 1,3 - 噻唑 - 2 - 基)氨基甲酰基]苯基乙酸酯(25N2LCPA)的固相傅里叶变换红外光谱(FTIR)和傅里叶变换拉曼光谱(FT - Raman)。进行了简正坐标分析以确认归属的准确性。进行了密度泛函理论(DFT)计算,给出了能量、优化结构、谐振动频率和红外强度。使用B3LYP方法和6 - 31 + G(d,p)基组,通过密度泛函理论(DFT)对分子结构进行了优化并确定了结构特征。借助按比例缩放的量子力学力场方法,通过简正坐标分析(NCA)对振动光谱进行了详细解释。以上述方法计算振动频率,并与实验频率进行比较,结果表明观测频率与计算频率吻合良好。使用自然键轨道(NBO)分析对由超共轭相互作用和电荷离域产生的分子稳定性进行了分析。此外,使用密度泛函理论(DFT)B3LYP/6 - 31 + G(d,p)基组计算了前线分子轨道和分子静电势。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)能量表明分子中发生了电荷转移。