Using a dual beam diode-laser spectrometer, we have studied with accuracy the N2-shift coefficients in the P-branch of the υ3 band of methane. The experiments were performed at room temperature for 16 lines in the spectral range 2906-2948 cm-1 with J values between 7 and 11. Each line was recorded at four different nitrogen pressures ranging from 17 to 302 mbar. The collisional shifts were obtained by fitting to the experimental lineshape a Rautian-Sobel'Man profile that takes into account the Dicke narrowing. The shift coefficients were determined using a procedure where a non perturbed line of pure CH4 was simultaneously recorded with N2-shifted transitions. Finally, we give a comparison with previous published results.
- Diode-laser spectroscopy
- Line shifts