THE ABSORPTION-SPECTRUM OF THE NITRATE (NO3) RADICAL IN AQUEOUS-SOLUTION

Absorption coefficients for the nitrate (NO3) radical in aqueous solution have been determined using multichannel optical absorption in the range lambda = 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 PHI (NO3) = (0.85 +/- 0.09) has been determined using a Br- scavenging technique. With this value the absolute absorption coefficient of NO3 at the maximum of its absorption at 635 nm was found as epsilon = (527 +/- 105) l/mol.cm (base 10). Absorption coefficient 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 has been calculated to be (1.6 +/- 0.5) . 10(-3) in reasonable agreement with the gas phase value.