Month: September 2022

"THE BIRTH OF A CRYSTAL —the so-called nucleation process—is one of the most fascinating problems in protein crystallization...the mechanisms leading to the formation of clusters of molecules displaying translational and rotational order have their own rules completely different from those of crystal growth." https://lnkd.in/eDMAEEh View in LinkedIn

CRYSTAL NUCLEATION "is the initiation of a phase change in a small region, such as the formation of a solid crystal from a liquid solution. It is a consequence of rapid local fluctuations on a molecular scale in a homogeneous phase that is in a state of metastable equilibrium." https://lnkd.in/eMnXY6A View in LinkedIn

STABLE LATTICE. "Exactly how a stable crystal nucleus is formed within a homogeneous fluid is not known with any degree of certainty. The formation of crystal nuclei is an even more difficult process to envisage. Not only have the constituent molecules to coagulate, resisting the tendency to redissolve, but they also have to become orientated into a fixed lattice." https://lnkd.in/eTDpY_Q View in LinkedIn

CRITICAL NUCLEUS. "The structure of the assembly of molecules or ions which we call a critical nucleus is not known, and it is too small to observe directly. It could be a miniature crystal, nearly perfect in form. On the other hand, it could be a rather diffuse body with molecules or solvated ions in a state not too different from that in the bulk fluid, with no clearly defined surface." https://lnkd.in/eTDpY_Q View in LinkedIn

PHASE CHANGE. "Nucleation is one of the two major mechanisms of the first order phase transition, the process of generating a new phase from an old phase whose free energy has become higher than that of the emerging new phase. Nucleation occurs via the formation of small embryos of the new phase inside the large volume of the old phase. Another prominent feature of nucleation is metastability of the old phase, i.e., the transformation requires passage over a free energy barrier." https://lnkd.in/eVX4ANS View in LinkedIn

LOWER ENERGY STATE. "Because the surface molecules are less well bound to their neighbors than are those in the bulk, their contribution to the free energy of the new phase is greater...But once the nucleus gets large enough, the drop in free energy associated with formation of the bulk phase becomes sufficiently high that the surface free energy is unimportant, and every addition of a molecule to the lattice lowers the free energy of the system." https://lnkd.in/eVX4ANS View in LinkedIn

TIME-LAPSE VIDEO of crystal growth. https://lnkd.in/eGv7J7A View in LinkedIn

"CRYSTALIZATION is a nucleated phenomenon; there is a positive free-energy activation barrier to the formation of a nucleus of a few hundred molecules. Once the nucleus has formed the growth process is thermodynamically favored." https://lnkd.in/eX2znvr View in LinkedIn

"THE SHAPES OF CRYSTALS are controlled by a combination of energetic and kinetic factors. The equilibrium shape is that which minimizes the total surface free energy of the crystal, which is in turn the sum of the individual products of surface area times interfacial energy. Thus low energy faces are preferentially expressed." https://lnkd.in/eVX4ANS View in LinkedIn

STRUCTURED WATER. "One other important factor worth discussing is the role of water. It has recently been realized that the structuring of water molecules around ions, molecules, and colloid-sized particles in dissolved state is an important factor in the thermodynamics of phase transitions in solution." https://lnkd.in/eVX4ANS View in LinkedIn