Theoretical Study on the Conformers and Thermal Distribution of NTO

• Main Authors: Gen-Fa Zheng, 鄭根發
• Other Authors: Cheng Chen
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/22088061297516151766

碩士 === 中正理工學院 === 應用化學研究所 === 88 === ABSTRACT Molecular orbital methods of semiempirical, ab initio and density functional theory (DFT) are selected from Gaussian 98 package to study the local minima of 5-Nitro-1,2,4-triazol-3-one (NTO). The structures and vibration frequencies of the most stable conformer are compared with the observed values of references by comparison of their standard deviation and relative standard deviation. The results indicated that the B3LYP level of density functional theory is the best calculation method with the less computational time. The 6-311+G(2d,p) and B3LYP/6-31G** basis sets of B3LYP level calculations have been carried out to investigate the conformers, and it is found that the all 26 conformers have 24 planar structures. Most of them have the conjugated stable specialty withπmolecular orbital delocalization. When the analysis of thermal distribution for the all calculated 26 NTO conformers. We find that only the most stable conformer exists at room temperature, but there are 11 conformers coexist when the temperature increases to 2000 K. Especially, the conformers which have large entropy have the feature of highly exist proportion. The phenomenon, the conformers coexisting at high temperature, is possibly the principle reason why NTO is stable and insensitive.