ABSOLUTE DETERMINATION OF THE TEMPERATURE BEHAVIOR OF THE NO2--]N2O5+(M) EQUILIBRIUM(NO3+(M)[)

The temperature dependence of the NO2 + NO3 + (M) <-> N2O5 + (M) equil ibrium has been studied in the temperature range 279.6-294.2 K at a to tal pressure of 1000 mbar synthetic air in the 200 m(3) EUPHORE simula tion chamber facility in Valencia, Spain. Simultaneous determination o f the concentration-time behaviors of NO3, NO2, and N2O5 were obtained using the DOAS technique for detection of the NO3 radical and FT-IR s pectroscopy for detection of NO2, and N2O5. The experimental data are well described by ln([N2O5]/[NO2][NO3]) = -60.46 +/- 0.26 + (10724 +/- 75)/T where the errors given are random and expressed as 95% confiden ce limits. A critical comparison, is made between the values of K-eq d etermined in this work and those reported in the literature.