Absorption coeffs. for the NO radical in aq. soln. were detd. using multichannel optical absorption in the range l = 540-760 nm. NO3 radicals were generated by excimer laser photolysis of (NH4)2[Ce(NO3)6] at 351 nm. For the quantum yield of NO3 formation from this process, a value of F (NO3) = (0.85 +- 0.09) was detd. using a Br- scavenging technique. With this value, the abs. absorption coeff. of NO3 at the max. of its absorption at 635 nm was e = (527 +- 105) L/mol.cm (base 10). Absorption coeff. data for the range 540-760 nm are presented in 2 nm intervals. The oscillator strength of the (0-0) band transition near 665 nm was (1.6 +- 0.5).10-3 in reasonable agreement with the gas phase value.