HF cross sections Alan Heays 2017-03-08  An absolute photoabsorption cross section for the continuum A-X absorption is recorded by nee1985c between 112 and 145 nm, and the entire VUV photoabsorption spectrum is measured by electron-energy-loss spectroscopy by hitchcock1984, but with an 2 times greater absolute magnitude fro the A-X transition. Subsequent calculations of the A-X transition (brown2000a, li_yuanjun2010) clearly favour the absolute magnitude (and absorption) profile of the nee1985c A-X measurement. I have then downscaled the entire spectrum of hitchcock1984 to match this (a factor of 0.53).  The photoabsorption recorded by nee1985c is extrapolated linearly from 145 to 165\,nm to match the approximately point where the calculated cross sections of brown2000a and li_yuanjun2010 become zero.  A photoionisation yield measured by berkowitz1971 was rescaled by a factor of 1.47e-17 to match the cross section of hitchcock1984 (itself already rescaled) at its shortest wavelength, 62.5 nm.  We assume 100% for this wavelength and shorter, which is roughly consistent with the branching measured by carnovale1981b.  I judge the overall uncertainty of the cross section to be about 30%.  References: nee1985c http://stacks.iop.org/0022-3700/18/i=10/a=006, hitchcock1984 10.1016/0301-0104(84)85104-6, berkowitz1991 10.1063/1.1674811 , brown2000a 10.1063/1.482075, li_yuanjun2010 10.4208/jams.012510.021610a wavelength:        (nm) photoabsorption:   Photoabsorption cross section (cm2) photodissociation: Photodissociation cross section (cm2) photoionisation:   Photoionisation cross section (cm2)
2
   0       934.12690     1.84942e-16
   1       953.83901     1.59072e-16
72
-1
   0   912.00000  0.000e+00
   1   954.57406  0.000e+00
   2   964.57406  5.928e-20
   3   974.57406  1.859e-19
   4   984.57406  1.451e-19
   5   994.57406  8.208e-20
   6  1004.57406  1.322e-19
   7  1014.57406  2.006e-19
   8  1024.57406  3.091e-19
   9  1034.57406  4.364e-19
  10  1044.57406  5.448e-19
  11  1054.57406  6.922e-19
  12  1064.57406  8.239e-19
  13  1074.57406  1.002e-18
  14  1084.57406  1.135e-18
  15  1094.57406  1.395e-18
  16  1104.57406  1.704e-18
  17  1114.57406  2.062e-18
  18  1124.57406  2.446e-18
  19  1134.57406  2.747e-18
  20  1144.57406  3.009e-18
  21  1154.57406  3.192e-18
  22  1164.57406  3.338e-18
  23  1174.57406  3.425e-18
  24  1184.57406  3.465e-18
  25  1194.57406  3.442e-18
  26  1204.57406  3.334e-18
  27  1214.57406  3.140e-18
  28  1224.57406  2.903e-18
  29  1234.57406  2.580e-18
  30  1244.57406  2.308e-18
  31  1254.57406  1.996e-18
  32  1264.57406  1.742e-18
  33  1274.57406  1.467e-18
  34  1284.57406  1.225e-18
  35  1294.57406  1.005e-18
  36  1304.57406  8.240e-19
  37  1314.57406  6.446e-19
  38  1324.57406  5.282e-19
  39  1334.57406  4.261e-19
  40  1344.57406  3.539e-19
  41  1354.57406  3.063e-19
  42  1364.57406  2.781e-19
  43  1374.57406  2.574e-19
  44  1384.57406  2.415e-19
  45  1394.57406  2.232e-19
  46  1404.57406  2.025e-19
  47  1414.57406  1.817e-19
  48  1424.57406  1.731e-19
  49  1434.57406  1.745e-19
  50  1444.57406  1.623e-19
  51  1454.57406  1.512e-19
  52  1464.57406  1.446e-19
  53  1474.57406  1.368e-19
  54  1484.57406  1.291e-19
  55  1494.57406  1.213e-19
  56  1504.57406  1.135e-19
  57  1514.57406  1.057e-19
  58  1524.57406  9.792e-20
  59  1534.57406  9.013e-20
  60  1544.57406  8.235e-20
  61  1554.57406  7.456e-20
  62  1564.57406  6.678e-20
  63  1574.57406  5.899e-20
  64  1584.57406  5.120e-20
  65  1594.57406  4.342e-20
  66  1604.57406  3.563e-20
  67  1614.57406  2.785e-20
  68  1624.57406  2.006e-20
  69  1634.57406  1.228e-20
  70  1644.57406  8.385e-21
  71  1649.73000  2.102e-22