On the Pressure and Temperature Dependence of the Absorption Coefficient of NH3

[摘要] The effects of pressure and temperature on the absorption coefficient of ammonia (NH3) gas self-perturbed and perturbed by nitrogen (N2) gas have been measured. We varied the gas pressure from 10 to 160 Torr and the temperature from 235 to 296 K in order to study the absorption coefficient at the center and the wings of lines in theν4band of NH3. These measurements were made using a high resolution (0.0038 cm−1) Bruker Fourier-transform spectrometer. These spectra have been analyzed using the method of multipressure technique permitting to succeed to an evolution of the absorption coefficient with the pressure and the quantum numbersJandKof the NH3molecule. The results show that the absorption coefficient varies as a quadratic function of the pressure at the center of a given line. However, it has a linear evolution in the wings of the line. Moreover, the absorption coefficients are inversely proportional to temperature in the wings when NH3lines are broadened by N2. The retrieved values of these coefficients were used to derive the temperature dependence of N2broadening NH3lines. The absorption coefficients were shown to fit closely the well-known exponential law.

[学科分类] 光谱学