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In general, sublimation is a phase change of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. Sublimation is an endothermic phase change that occurs at temperatures and pressures below a substance’s triple point in its phase diagram.

Consider the ice at -10°C  and at the pressure of 500 Pa. In this case, heat transfer to the ice first results in an increase in temperature to -8°C. At this point, however, the ice passes directly from the solid phase to the vapor phase in the process known as sublimation. The corresponding heat is called the heat of sublimation, Ls. Further heat transfer would result in superheating the vapor.

Since sublimation is an endothermic phase change, it requires additional energy. This additional energy required can be calculated by adding the enthalpy of fusion and the enthalpy of vaporization and is known as the enthalpy of sublimation (also called heat of sublimation).

For some substances, sublimation is much easier than evaporation from the melt. It depends on their triple point. When the pressure of its triple point is too high,  it is difficult to obtain them as liquids.

The reverse process of sublimation is desublimation, in which a substance passes directly from a gas to a solid phase.

Reactor Physics and Thermal Hydraulics:
  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. Todreas Neil E., Kazimi Mujid S. Nuclear Systems Volume I: Thermal Hydraulic Fundamentals, Second Edition. CRC Press; 2 edition, 2012, ISBN: 978-0415802871
  6. Zohuri B., McDaniel P. Thermodynamics in Nuclear Power Plant Systems. Springer; 2015, ISBN: 978-3-319-13419-2
  7. Moran Michal J., Shapiro Howard N. Fundamentals of Engineering Thermodynamics, Fifth Edition, John Wiley & Sons, 2006, ISBN: 978-0-470-03037-0
  8. Kleinstreuer C. Modern Fluid Dynamics. Springer, 2010, ISBN 978-1-4020-8670-0.
  9. U.S. Department of Energy, THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW. DOE Fundamentals Handbook, Volume 1, 2 and 3. June 1992.

See above:

Phase Changes