Investigation of J dependence of line shift, line broadening, and line narrowing coefficients in the nu(1)+3 nu(3) absorption band of acetylene

Line shift coefficients, line broadening coefficients, and line narrowing c oefficients have been measured in the nu (1) + 3 nu (3) band of acetylene u sing a diode laser system operating at 788 nm and a multipass Herriot absor ption cell. Experimental data have been obtained for 20 lines of the P and R branches broadened by N-2, O-2, air, and the rare gases He, Ne, Ar, Kr, a nd Xe. The observed line shapes could successfully be reproduced by employi ng Galatry and Rautian functions which include the phenomenon of Dicke narr owing. Our results for the line broadening coefficients are in good agreeme nt with the values reported previously for other vibrational bands. Thus, t he present work confirms the vibrational independence of the broadening coe fficients. On the other side, we observed a clear dependence of the narrowi ng coefficients on rotation in a vibrational transition of acetylene for th e first time. In addition, the line center frequencies have been determined with improved accuracy. (C) 2001 American Institute of Physics.