Sebastian S, Sylvestre S, Jayabharathi J, Ayyapan S, Amalanathan M, Oudayakumar K, Herman Ignatius A
Department of Physics (Science and Humanities), Sri Manakula Vinayagar Engg. College, Madagadipet, Puducherry 605 107, India.
Department of Chemistry, DMI-St. Eugene University, Chipata 511 026, Zambia.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt B:1107-18. doi: 10.1016/j.saa.2014.09.135. Epub 2014 Oct 28.
In this work we analyzed the vibrational spectra of 3,5-dinitrosalicylic acid (3,5DNSA) molecule. The total energy of eight possible conformers can be calculated by Density Functional Theory with 6-31G(d,p) as basis set to find the most stable conformer. Computational result identify the most stable conformer of 3,5DNSA is C6. The assignments of the vibrational spectra have been carried out by computing Total Energy Distribution (TED). The molecular geometry, second order perturbation energies and Electron Density (ED) transfer from filled lone pairs of Lewis base to unfilled Lewis acid sites for 3,5-DNSA molecular analyzed on the basis of Natural Bond Orbital (NBO) analysis. The formation of inter and intramolecular hydrogen bonding between OH and COOH group gave the evidence for the formation of dimer formation for 3,5-DNSA molecule. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincides with the experimental spectra.
在这项工作中，我们分析了3,5 - 二硝基水杨酸（3,5DNSA）分子的振动光谱。通过密度泛函理论，以6 - 31G(d,p)为基组计算了八种可能构象异构体的总能量，以找出最稳定的构象异构体。计算结果表明3,5DNSA最稳定的构象异构体是C6。通过计算总能量分布（TED）对振动光谱进行了归属。基于自然键轨道（NBO）分析，对3,5 - DNSA分子的分子几何结构、二阶微扰能量以及从路易斯碱的孤对电子到未填充的路易斯酸位点的电子密度（ED）转移进行了分析。OH和COOH基团之间分子间和分子内氢键的形成证明了3,5 - DNSA分子二聚体的形成。通过含时密度泛函理论（TD - DFT）计算的能量和振子强度与实验结果相互补充。模拟光谱与实验光谱令人满意地吻合。
