Zone growth: A simple procedure for growing organic crystals from the melt of from the vapour phase

Zboiński, Zbigniew

doi:10.1016/0022-0248(82)90280-9

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…The mentioned non-equilibrium states, or metastable states, complicate the determination of equilibrium phase diagrams, requiring efforts to prepare mixtures with a high degree of homogeneity [6,7]. It has also led to the method implemented in the software program LIQFIT for the determination of excess parameters by fitting experimental data, which is based on fitting only the liquidus points and not the solidus points which are considered unreliable [8].…”

Section: Introductionmentioning

confidence: 99%

Models for the determination of kinetic phase diagrams and kinetic phase separation domains

Los

Heuvel

Enckevort

et al. 2006

Calphad

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Several theoretical models for the determination of kinetic phase diagrams for solid solution growth from the liquid phase are presented and compared to each other. These models include a Monte Carlo simulation model, used as a reference model, a previously defined analytical model, based on linear non-equilibrium thermodynamics, and a new model, rooted in the kinetics at kink sites.All models have in common that the composition of the growing solid phase tends to the liquid phase composition for increasing undercooling, enhancing mixing even for systems with a strong tendency to phase separation. However, depending on the system parameters considerable quantitative differences can occur between the results from the model based on non-equilibrium thermodynamics and the MC model. Instead, the new model follows very well the trends of the MC simulations, both for well-mixing systems and for phase separating systems.For phase separating systems the analytical models predict kinetic phase separation domains, zones in the kinetic phase diagram yielding steady state growth of more than one solid phase with different compositions. According to MC simulations such domains in phase space correspond to domain formation in real space. Also in this case the new model is consistent with the MC results.

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Section: Introductionmentioning

confidence: 99%

Models for the determination of kinetic phase diagrams and kinetic phase separation domains

Los

Heuvel

Enckevort

et al. 2006

Calphad

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“…Several studies on the binary mixture of our interest, 1,4-dichlorobenzene and 1,4-dibromobenzene, demonstrate methods for determination of the equilibrium phase diagram [1][2][3][4]. Measuring equilibrium solidus and liquidus lines by melting samples is a laborious work in the sense of preparing mixtures of a high degree of homogeneity [5][6][7], while there is always uncertainty about whether the system has reached the equilibrium during measurements. As for the melting and crystallization of the molecular mixed crystals, the problem arises due to very low diffusion rates in the solid phase [8] that prevent overall equilibrium between the entire amounts of solid and liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Kinetic approach to the determination of the phase diagram of a solid solution

Matovic

Miltenburg

Oonk

et al. 2006

Calphad

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A binary mixture of 1,4-dichlorobenzene and 1,4-dibromobenzene, as a representative of a system that forms a solid solution, was measured in an adiabatic calorimeter. Several mixtures of different compositions were heated to 380 K, kept in the liquid phase at this temperature overnight, and then cooled slowly down to 250 K. The enthalpy path of the mixture measured during cooling carries the information that enables us to describe the crystallization process. In the first stage, crystallization develops rapidly and clearly deviates from equilibrium, while in the second stage it proceeds significantly slower, whereby we assume that the surface of the solid is in equilibrium with the existing liquid phase at the given temperature during cooling. Such an approach opposes the one that assumes equilibrium between the liquid and solid bulks, known as the equilibrium model. We show that by employing the kinetic model, the experimental enthalpy path of the mixture during cooling in the adiabatic calorimeter can be very successfully reproduced, while the equilibrium model fails in this aspect. Furthermore, we propose a procedure where the kinetic model is used to obtain the excess thermodynamic properties of the solid phase. These quantities enable the calculation of the liquid-solid phase diagram using the excess parameters obtained from the approach that does not assume the overall equilibrium between the phases during the crystallization process.

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Are new chemical species in anthracene crystals formed as a result of charge-carrier trapping at physical defects?

Zboiński

1983

Chemical Physics

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Zone growth: A simple procedure for growing organic crystals from the melt of from the vapour phase

Cited by 3 publications

References 2 publications

Models for the determination of kinetic phase diagrams and kinetic phase separation domains

Models for the determination of kinetic phase diagrams and kinetic phase separation domains

Kinetic approach to the determination of the phase diagram of a solid solution

Are new chemical species in anthracene crystals formed as a result of charge-carrier trapping at physical defects?

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