Rate coefficients for deactivation of SO(X(3)Sigma(-), nu = 1-5) by collisions with SO2 and nascent vibrational populations in nu = 0-2 in the photolysis of SO2 at 193.3 nm have been determined. A single vibrational level of SO(X(3)Sigma(-)) was detected with laser-induced fluorescence (LIF) excited via the B(3)Sigma(-)-X(3)Sigma(-) system. Time-dependent profiles of LIF signals were recorded as a function of the pressures of SO2. Observed profiles were analyzed by the integrated-profiles method and reproduced well by convolution calculations. Overall rate coefficients for vibrational relaxation of SO(nu) by SO2 have been determined to be (4.7 +/- 0.5) x 10(-12) (nu = 1), (6.7 +/- 0.4) x 10(-12) (nu = 2), (7.2 +/- 0.7) x 10(-12) (nu = 3), (6.1 +/- 1.0) x 10(-12) (nu = 4), and (8.6 +/- 0.7) x 10(-12) (nu = 5) in units of cm(3) molecule(-1) s(-1) (the quoted errors are 2sigma). We have also found that 63% of the vibrational deactivations of nu = 2 by SO2 are governed by double-quantum relaxation: (4.2 +/- 0.9) x 10(-12) cm(3) molecule(-1) s(-1) for nu = 2 --> nu = 0 and (2.5 +/- 0.9) x 10(-12) cm(3) molecule(-1) s(-1) for nu = 2 --> nu = 1. Ab initio calculations enable us to find two stable complexes: OS-OSO and SO-SO2, indicating that attractive interactions play a significant role in the relaxation. The nascent vibrational distributions of SO have been measured to be 0.52 +/- 0.1/0.75 +/- 0.1/1.0 for nu = 0/1/2. The differences in vibrational distributions reported by bulk and beam experiments are attributed to the difference in the temperature of parent SO2.