Compute the number of ice monolayers

Ice monolayers.ipynb

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    "from math import pi\n",
    "\n",
    "nh = 4.06e9 # Hydrogen number density\n",
    "xd = 1.3e-12 # Grain abundance\n",
    "Ns = 3e15 # Number of sites per cm^-2\n",
    "rd = 0.1  # Grain radius in microns\n",
    "\n",
    "rd *= 1e-4 # microns -> cm"
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    "Let us compute the abundance that corresponds to one ice monolayer. The surface of one monolayer is given by:"
   ]
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   "source": [
    "monolayer_surface = 4 * pi * rd**2 # cm^2"
   ]
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   "source": [
    "The number of molecules per monolayer is then:"
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    "mol_per_monolayer = monolayer_surface * Ns"
   ]
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   "source": [
    "In order to get the number of molecules per unit volume (i.e the abundance), we multiply this number by the grain abundance:"
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     "text": [
      "1.2252211349e-06\n"
     ]
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   "source": [
    "x_monolayer = mol_per_monolayer * xd\n",
    "print x_monolayer"
   ]
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   "source": [
    "So one monolayer corresponds to an abundance of 1.2 x 10<sup>-6</sup>. Note that this number does not depend on the hydrogen number density, but only on the grain radius and the grain abundance. Since we measure CO abundances of about 10<sup>-5</sup>, this means that we have about **10 monolayers of CO ices**."
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