Pathways of Structural Transformations in Reconstructive Phase Transitions: Insights from Transition Path Sampling Molecular Dynamics

Modeling Diffusion of Linear Hydrocarbons in Silica Zeolite LTA Using Transition Path Sampling

“…Molecular dynamics at high temperature can be used to increase the frequency of the transition event and obtain a first pathway. , However, lowering the temperature to the desired value during the sampling can lead to frequent unsuccessful transition paths, reducing the overall efficiency of the calculations. The symmetry of the stable states A and B can be used to generate geometric intermediate configurations to derive a first trajectory. − In this work, the molecule was placed at the center of one of the cubic cell faces at crystallographic special position 3 c (0, 1/2, 1/2), which corresponds to the center of the 8MR. Then the system was propagated forward (+ t ) and backward (− t ) in time.…”

Structure, Bonding, and Mineralogy of Carbon at Extreme Conditions

“…The metastable high-pressure phase is formed solely because it has the lowest activation barrier at the indicated P-T conditions (e.g., 15 GPa and 300 K). Using transition path sampling (Dellago et al 1998;Leoni and Boulfelfel 2010;Boulfelfel et al 2012) found that the likeliest sp 3 structure of carbon to be formed by room-temperature compression of graphite-2H is indeed M-carbon. Boulfelfel et al (2012) predict this transition has a lower energy barrier than transitions to other structures.…”

Introduction: Crystal Structure Prediction, a Formidable Problem

“…Both structures are metastable and both match experimental observations almost equally well, but nevertheless there is a way of deciding which one is more likely to be the ''superhard graphite'' of Mao [41]. The best approach for computing the absolute activation energies of solid-solid phase transitions is the transition path sampling method [42], reviewed in this volume by Leoni and Boulfelfel [43]. Indeed, the structure with optimal properties will frequently be metastable, and will be of interest only if it can be synthesized.…”

“…Indeed, the structure with optimal properties will frequently be metastable, and will be of interest only if it can be synthesized. It is my hope that this volume, reviewing most of the major methods of crystal structure prediction, all the way from topological approaches [4] to optimization methods [19,22,25,27,29,32] and methods to appraise synthesizability of a material [43], will be useful to a wide readership of physicists, chemists, materials scientists and earth scientists. The best approach for computing the absolute activation energies of solid-solid phase transitions is the transition path sampling method [42], reviewed in this volume by Leoni and Boulfelfel [43].…”