37 23
Reference: JPL Publication 94-26
           Chemical Kinetics and Photochemical Data for Use in Stratospheric
           Modeling
           Evaluation Number 11
           December 15, 1994
           page 130 ff.

CH2O + hv -> H + HCO  (Phi1)
          -> H2 + CO  (Phi2)

"The earlier recommendation for the formaldehyde absorption cross sections was
based on the work carried out by Bass et al. [116] with a resolution of 0.05 nm
at 296 K and 223 K, and by Moortgat et al. [1121, 1124] with a resolution of
0.5 nm in the 210-360 K temperature range.  More recently, Cantrell et al.
[250] measured the cross sections in the 300-360 nm range between 223K and 293
K, and Rogers [1338] measured the cross sections in the 235-365 nm range at 296
K, both groups using Fourier transform spectrometry at a resolution of up to
0.011 nm (1 cm-1).  The agreement between these two reports is very good.  The
recommended values are those given by Cantrell et al. as a function of
temperature;  the reader is referred to the original article to obtain the high
resolution data.  Table 22 lists the low resolution cross sections taken from
that work, which are suitable for atmospheric photodissociation calculations."

Table 22.  Absorption Cross Sections and Quantum Yields for Photolysis of CH2O

Note:  The values are averaged for 2.5 nm intervals centered on the indicated
wavelength.

* Cross sections for -50 C < T < 20 C calculated as sigma(T) = A + Bx1E-3xT

===============================================================================
                  1E20 sigma (cm^2)               T-parameters *
lambda        -------------------------       ---------------------
(nm)  		223 K		293 K		A		B
===============================================================================
301.25		1.38		1.36		1.37		-0.21
303.75		4.67		4.33		4.43		-4.73
306.25		3.32		3.25		3.27		-1.06
308.75		2.27		2.22		2.24		-0.724
311.25		0.758		0.931		0.882		 2.48
313.75		3.65		3.40		3.47		-3.64
316.25		4.05		3.89		3.94		-2.30
318.75		1.66		1.70		1.69	  	 0.659
321.25		1.24		1.13		1.16		-1.52
323.75		0.465		0.473		0.471		 0.118
326.25		5.06		4.44		4.61		-8.86
328.75		2.44		2.29		2.34		-2.15
331.25		1.39		1.28		1.31		-1.53
333.75		0.093		0.123		0.114		 0.432
336.25		0.127		0.131		0.130		 0.050
338.75		3.98		3.36		3.54		-8.96
341.25		0.805		0.936		0.898		1.86
343.75		1.44		1.26		1.31		-2.64
346.25		0.004		0.071		0.052		 0.957
348.75		0.009		0.040		0.031		 0.438
351.25		0.169		0.235		0.216		 0.948
353.75		1.83		1.55		1.63		-4.05
356.25		0.035		0.125		0.099		 1.27