N2O5 absorption cross section at 300 K, from JPL3011.
The temperature dependence coefficients are given for a few wavelengths 
after the cross section data (bottom of file)
nm      1e-20 cm2 / molecule
200	910
202	842
204	771
206	682
208	585
210	445
212	381
214	322
216	267
218	220
220	181
222	151
224	129
226	113
228	98.4
230	88.2
232	80.5
234	74
236	69.2
238	64.6
240	59.8
242	53.1
244	49.3
246	45.6
248	41.9
250	38.6
252	35.5
254	32.6
256	29.9
258	27.5
260	25.2
262	23.1
264	21.1
266	19.4
268	17.8
270	16.2
272	14.9
274	13.7
276	12.4
278	11.4
280	10.5
282	9.59
284	8.74
286	7.94
288	7.2
290	6.52
292	5.88
294	5.29
296	4.75
298	4.26
300	3.81
302	3.4
304	3.03
306	2.7
308	2.4
310	2.13
312	1.9
314	1.68
316	1.49
318	1.33
320	1.18
322	1.05
324	0.93
326	0.826
328	0.735
330	0.654
332	0.582
334	0.518
336	0.462
338	0.412
340	0.368
342	0.328
344	0.293
346	0.262
348	0.234
350	0.21
352	0.188
354	0.167
356	0.149
358	0.133
360	0.12
362	0.107
364	0.0958
366	0.0852
368	0.0763
370	0.0685
372	0.0613
374	0.0545
376	0.0484
378	0.0431
380	0.0383
382	0.0341
384	0.0305
386	0.0273
388	0.0242
390	0.0215
392	0.0193
394	0.0172
396	0.015
398	0.0134
400	0.014
410	0.009
420	0.005
**************************
Temperature dependence coefficients, for use in formula:
log10(sigma(lambda)) = A(lambda) + 1000 B(lambda)/T  valid over 233-295K.
nm 	    A	       B, K-1
260.	    -18.27     -0.091
270.	    -18.42     -0.104
280.	    -18.59     -0.112
290.	    -18.72     -0.135
300.	    -18.84     -0.170
310.	    -18.90     -0.226
320.	    -18.93     -0.294
330.	    -18.87     -0.388
***************