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[62.07] The Heat of Sublimation of solid Methane from 63 to 90 K

R. N. Nelson (NASA - GSFC / CUA), J. E., Jr. Allen, (NASA - GSFC)

Light hydrocarbons are important in the development of atmospheres, clouds, hazes, and surface layers in the outer planets and some of their satellites. The first-order equilibrium and photochemical models developed to describe these systems require accurate laboratory data as inputs. It is important that these data are acquired over the appropriate range of atmospheric parameters, e.g., temperature and pressure. There is a particular need for vapor pressures of molecular constituents at low temperatures, and the behavior of surface layers specifically requires information on the heat of sublimation of the solid phase. Previously we reported preliminary results for the vapor pressure of methane (Allen and Nelson 1998). We have now refined those data and used them to evaluate the heat of sublimation of methane from 62.5 K to the triple point at 90.3 K.

Allen, J. E., Jr. and Nelson, R. N. 1998, Proc. of the NASA Laboratory Space Science Workshop (Cambridge: Harvard-Smithsonian).

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