The Measurement And Calculation Of The Infrared Spectra Of HCl Gas

HCl gas is toxic and strongly corrosive.It is of great need to monitor the concentration of HCl in production and environmental warnings.By observing the frequency and intensity of the infrared spectrum of the gas,the type and concentration of the gas can be determined.Fourier transform infrared spectroscopy(FTIR)is featured in high precision,wide applicability,rapid response,long life and easy use.It is an ideal detection method in the field of gas analysis.In this thesis,we use FTIR to measure the HCl gas spectrum on one hand.On the other hand,we compare the experimental results with the calculated results,and study the possibility and reliability of predicting the gas spectral characteristics by calculation.The main research work and results are as follows:A high-temperature gas spectrometry test system was set up,and special measures were taken for the sealing of gas cell and the ventilation of the liboratory for toxic gases.The infrared emission spectrum of HCl gas was measured by Fourier transform infrared technology.The high-resolution infrared emission spectrum of HCl gas at different temperatures and concentrations was obtained,which enriched the spectral library of HCl.The vibrational spectrum of HCl gas was calculated by first-principles molecular dynamics under the same temperatures and concentrations corresponding to the experimental ones.By comparing the measured and calculated spectral lines and the peak position of the spectral band,band integral energy and other eigenvalue-related data,it is found that the HCl band envelope obtained by molecular dynamics is in good agreement with the experimental results.There are appreciable errors in the calculation of the peaks in the middle part of the band,the peaks located in the two vibration branches,and the integral energy of each branch.This indicates that the calculation can assist to preliminarily identify the gas by comparison with the detected infrared spectrum.For more accurate identification,it is necessary to improve the calculation method or directly compare it with the library of the measured infrared spectra.