SELF-BROADENING AND AIR-BROADENING IN THE NU(3)-BAND OF SO2

The quantum number dependence of self- and air-broadening coefficients of 33 transitions in the nu(3) band of SO2 with 4 less than or equal to J '' less than or equal to 61, 0 less than or equal to K-a '' less than or equal to 18 was measured with a pulse-driven diode laser spect rometer. Twenty-five lines of the P-branch, five lines of the R-branch , and three lines of the Q-branch were studied. The self-broadening co efficients gamma(so2-so2) vary between 0.151 and 0.498 cm(-1)/atm. For small K-a '' values the self-broadening coefficients gamma(so2-so2) s how a strong scattering of data, whereas a pronounced decrease with in creasing quantum number K-a '' was found for lines with K-a '' greater than or equal to 10. For K-a '' values of about 3, the largest broade ning coefficients were measured. No significant tendency in the J '' d ependence was found. Quantum number dependence and absolute values are in good agreement with previous experimental results for the nu(1) ba nd of SO2. The situation in the case of collisions with air is similar , where the gamma(so2-air) values vary between 0.061 and 0.130 cm(-1)/ atm and no significant dependence of the broadening coefficients was o bserved as in the case of the nu(1) band. (C) 1996 Academic Press, Inc .