The formation of straight gallium nitride nanorods in the presence of ammonium relies upon this phenomenon, and one method of obtaining a heat transfer coefficient involves analyzing this process in naphthalene.  In addition to oxidation, this process limits the utility of arsenic as a doping agent in low-resistivity crystal growth.  When this technique is used in classroom purifications of caffeine, it is followed by the use of a cold finger to permit the collection of caffeine as it condenses.  The enthalpy of this can be determined by adding the enthalpies of vaporization and fusion.  For 10 points, name this phase transition in which a so
The formation of straight gallium nitride nanorods in the presence of ammonium relies upon this phenomenon, and one method of obtaining a heat transfer coefficient involves analyzing this process in naphthalene.  In addition to oxidation, this process limits the utility of arsenic as a doping agent in low-resistivity crystal growth.  When this technique is used in classroom purifications of caffeine, it is followed by the use of a cold finger to permit the collection of caffeine as it condenses.  The enthalpy of this can be determined by adding the enthalpies of vaporization and fusion.  For 10 points, name this phase transition in which a solid changes directly into a gas without becoming a liquid.
The formation of straight gallium nitride nanorods in the presence of ammonium relies upon this phenomenon, and one method of obtaining a heat transfer coefficient involves analyzing this process in naphthalene.  
sublimation (accept word forms)