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Sputtering of Atoms and Molecules (ed. P. Sigmund) Mat-fys. Medd 43 Mem (Roy. Dan. Soc.,
Copenhagen) (1993) pp. 403-494.

Johnson, R.E. "Sputtering and Desorption from Icy Surfaces" Rev. Mod. Phys. 68 (1996) p. 305-312.

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       If you have new data contact Min Liu (ml7q@virginia.edu).

      Y is the amount of material removed given as the number of equivalent molecules ejected from
the solid per ion incident.  The data is typically fit using the values for of the energy loss per unit path
of the ion in the material, [dE/dx], from the SRIM package
( http://www.SRIM.org).
Sputtering of ices occurs due to both electronic and collisional (nuclear) energy loss by the incident
ion on penetrating the solid.  It also depends on temperature. At low temperatures the yield becomes
temperature independent, and the form

Yo= Cn [dE/dx]n^p + Ce [dE/dx]e^q

is typically used, where Cn, Ce and the powers p and q are fitting constants.  These constants can
be different for protons, but among the heavy ions a single set of constants roughly fits the data for a
number of target materials. Therefore, data for missing ions or energies can be obtained by the fittng
available data.  The dependence on temperature can be roughly fit using an Arhenius law

Y = Yo + Yx exp ( - U/kT )

with Yx and U obtained by fitting.

The yield can also be more simply fit as a function of velocity at a given temperature  See the table
for fitting parameters

      Except for low velocing heavy ions, C1 is found to vary, roughly as (cos (theta))^-1.6, where
theta is the angle of incidence.

      Care must be taken in using these fits as all of the relevant molecular ices are chemically altered
by the ion bombardment.  The principal ejecta at low temperature is often the initial molecule.
Masses typically present in the ejecta are given at the end of each data set.