Line shift and mixing in the ν4 and 2ν2 band of NH3 perturbed by H2 and Ar

Pressure induced line shift and line mixing parameters have been measured for 66 rovibrational lines in the ν4 band and for 10 lines in the 2ν2 band of NH3 perturbed by H2 and Ar at room temperature (T = 296 K). These lines with J values ranging from 2 to 10 are located in the spectral range 1450-1600 cm−1. Experiments were made with a high-resolution Fourier transform spectrometer. The line shifts and line mixing parameters have been derived from the non-linear least-square multi-pressure fitting technique. The shift coefficients are compared with those calculated from the Robert-Bonamy formalism (RB). The results are generally in satisfactory agreement with the experimental data.