The Research on Infrared Spectrum of C4F7N by Combined Experimental and Theoretical Study

摘要

C₄F₇N/CO₂ gas mixture is a new type of environmentally friendly insulating medium, which has the potential to replace SF₆ and has received extensive attention from researchers. The insulation performance of C₄F₇N/CO₂ gas mixture is closely related to the concentration of C₄F₇N. Meanwhile, the gas-insulated electrical equipment with C₄F₇N/CO₂ gas mixture has been gradually been put into practical application. Therefore, it is of great engineering significance to quickly and accurately measure the concentration of C₄F₇N in the gas mixture. The gas quantitative detection based on spectroscopy has the advantages of fast detection speed, simple device and high reliability, which can meet the demand of gas detection technology in the power industry. However, as a new type of synthetic gas, it is currently unable to find the information of absorption spectrum of C₄F₇N in the spectral database, so it is impossible to realize the concentration detection of C₄F₇N/CO₂ gas mixture based on spectroscopy. In this paper, the infrared spectrum of C₄F₇N molecule is theoretically calculated by density functional theory, its molecular structure has been analyzed, and the spectral information of the infrared band is obtained. The accuracy of the calculation results is verified by experimental comparison. By analyzing the infrared absorption spectrum, the bands which are easy saturation or have large error in the detection of C₄F₇N/CO₂ gas mixture are excluded. The source band based on infrared spectroscopy for the detection was determined. This research provides a theoretical basis for the development of detection devices based on infrared spectroscopy for quantitative detection of C₄F₇N/CO₂ gas mixture.