Sublimation (phase transition)

About: Sublimation (phase transition) is a research topic. Over the lifetime, 8201 publications have been published within this topic receiving 126273 citations.

Enthalpies of Sublimation of Organic and Organometallic Compounds. 1910–2001

Abstract: A compendium of sublimation enthalpies, published within the period 1910–2001 (over 1200 references), is reported. A brief review of the temperature adjustments for the sublimation enthalpies from the temperature of measurement to the standard reference temperature, 298.15 K, is included, as are recently suggested values for several reference materials. Sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds.

Thermal Behavior of Methylammonium Lead- trihalide Perovskite Photovoltaic Light Harvesters

Abstract: Recently organic–inorganic hybrid perovskites have attracted attention as light harvesting materials in mesoscopic cells. While a considerable number of deposition and formation methods have been reported for the perovskite crystalline material, most involve an annealing step. As such, the thermal behavior of this material and its individual components is of crucial interest. Here, we examine the thermal properties of the CH3NH3PbX3 (X = I or Cl) perovskite using thermogravimetric analysis. The role of the precursors is exposed, and the effect of the formation of excess organic species is investigated. The sublimation behavior of the organic component is intensively scrutinized. Furthermore, differential scanning calorimetry is employed to probe the crystal phase structure, revealing subtle differences depending on the deposition method.

Improved prediction of heats of formation of energetic materials using quantum mechanical calculations.

Abstract: We present simple atom and group-equivalent methods that will convert quantum mechanical energies of molecules to gas phase heats of formation of CHNO systems. In addition, we predict heats of sublimation and vaporization derived from information obtained from the quantum-mechanically calculated electrostatic potential of each isolated molecule. The heats of sublimation and vaporization are combined with the aforementioned gas phase heats of formation to produce completely predicted condensed phase heats of formation. These semiempirical computational methods, calibrated using experimental information, were applied to a series of CHNO molecules for which no experimental information was used in the development of the methods. These methods improve upon an earlier effort of Rice et al. [Rice, B. M.; Pai, S. V.; Hare, J. Combust. Flame 1999, 118, 445] through the use of a larger basis set and the application of group equivalents. The root-mean-square deviation (rms) from experiment for the predicted group-equivalent gas phase heats of formation is 3.2 kcal/mol with a maximum deviation of 6.5 kcal/mol. The rms and maximum deviation of the predicted liquid heats of formation are 3.2 and 7.4 kcal/mol, respectively. Finally, the rms and maximum deviation of predicted solid heats of formation are 5.6 and 12.2 kcal/mol, respectively, an improvement in the rms of approximately 40% compared to the earlier Rice et al. predictions using atom equivalents and a smaller basis set (B3LYP/6-31G*).

Sublimation of silicon carbide to produce large, device quality single crystals of silicon carbide

Abstract: The present invention is a method of forming large device quality single crystals of silicon carbide. The sublimation process is enhanced by maintaining a constant polytype composition in the source materials, selected size distribution in the source materials, by specific preparation of the growth surface and seed crystals, and by controlling the thermal gradient between the source materials and the seed crystal.