Ar-Broadening of isotropic Raman lines in the v2 band of acetylene

Using a high resolution Raman spectrometer, we have measured Ar-broadening coefficients in the v2 Q branch of C2H2 for 22 lines at 295 K, 20 lines at 174 K, and 16 lines at 134 K. These lines with J values ranging from 1 to 23 are located in the spectral range 1970.9-1974.3 cm-1. The collisional widths are obtained by fitting each spectral line with a Rautian profile. The resulting broadening coefficients are compared with theoretical values arising from close coupling and coupled states calculations. A satisfactory agreement is obtained at room as well as at low temperatures, especially for odd J lines. By comparing broadening coefficients at 295, 174, and 134 K from a simple power law, the temperature dependence of these broadenings has been determined both experimentally, and theoretically. © 2004 Elsevier Inc. All rights reserved.Spanish DGI, project No. REN2002-01618.Peer Reviewe