40 71
Reference: JPL Publication 94-26
           Chemical Kinetics and Photochemical Data for Use in Stratospheric
           Modeling
           Evaluation Number 11
           December 15, 1994
           page 122 f.

NO3 + hv -> NO + O2 (1)
            NO2 + O (2)

"The absorption cross sections for the nitrate free radical, NO3, have been 
studied by (1) Johnston and Graham [778]; (2) Graham and Johnston [589]; (3)
Mitchell et al. [1096]; (4) Marinelli et al. [1030]; (5) Ravishankara and Wine
[1311]; (6) Cox et al. [365]; (7) Burrows et al. [227]; (8) Ravishankara and
Mauldin [1302]; (9) Sander [1360]; (10) Cantrell et al. [251]; and (11)
Canosa-Mas et al. [246].  The 1st and 4th studies required calculation of the
NO3 concentration by modeling a complex kinetic system.  The other studies are
more direct and the results in terms of intefrated absorption coefficients are
in good agreement.  The recommended value at 298 K and 662 nm, (2.00 +-
0.25)x1E-17 cm^2, is the average of the results of studies (4), (5) and (7)
through (11).  The values in the wavelength range 600-670 nm, shown in Figure 2
and listed in Table 15, were calculated using the spectra measured in studies
(8), (9) and (11), and normalizing the 662 nm value to the above average.  The
spectra obtained in other studies are consulted for a more extended wavelength
range.  The temperature dependence of the 662 nm band has been studied by
Ravishankara and Mauldin [1302], Sander [1360] and Cantrell et al. [251], while
the first two investigators observe the cross section at 662 nm to increase
with decreasing temperature, Cantrell et al. [251] found no measurable
dependence.  The reason for this discrepancy is not clear.

[...]

The spectroscopy of NO3 has been review by Wayne et al. [1688].  The reader is
referred to this work for a more detailed discussion of the cross section and
quantum yield data, and for estimates of the photodissociation rates as a
function of zenith angle."

Wavelength (nm)     Cross Section (1E-20 cm^2) at 298 K
600			258
601			263
602			302
603			351
604			413
605			415
606			322
607			225
608			170
609			153
610			192
611			171
612			202
613			241
614			242
615			210
616			190
617			189
618			208
619			229
620			292
621			450
622			941
623			1407
624			1139
625			796
626			703
627			715
628			702
629			672
630			638
631			470
632			344
633			194
634			142
635			128
636			159
637			191
638			193
639			162
640			121
641			99
642			91
643			93
644			92
645			85
646			72
647			69
648			60
649			51
650			49
651			52
652			55
653			61
654			76
655			93
656			131
657			172
658			222
659			356
660			658
661			1308
662			2000
663			1742
664			1110
665			752
666			463
667			254
668			163
669			113
670			85