Precise Measurements of Collision Parameters of Spectral Lines with a Spectrometer with Radioacoustic Detection of Absorption in the Millimeter and Submillimeter Ranges

摘要

The factors influencing the accuracy of determining the parameters of molecular lines with the use of a spectrometer with radioacoustic detection of absorption are analyzed. In addition, the following instrumental features of the spectrometer that were not studied earlier are analyzed: the dependence of the sensitivity of the radioacoustic cell on the pressure of the cell-filling gas and the frequency dependence of the radiation power in the cell at gas pressures lower than 10 Torr. Methods of mathematical simulation of the spectrometer's output signal at various gas pressures are considered. A technique for calibrating the dependence of the cell's sensitivity on the pressure based on measurements of the integrated absorption coefficient of molecular spectral lines is presented. With allowance for the considered features of the spectrometer, the parameters of the lines of rotational multiplet J = 9 of fluoroform in the ground vibrational state are studied at gas pressures of 0.01-10 Torr.