Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Collective displacements in a molecular crystal polymorphic transformation
AU - Zahn, Dirk
AU - Anwar, Jamshed
PY - 2013
Y1 - 2013
N2 - A long-standing question is whether concerted molecular displacements can occur during first-order phase transformations in molecular crystals. We have investigated the molecular level mechanism of the temperature-induced β → α phase transition in the molecular crystal DL-norleucine using molecular dynamics (MD) simulations. The simulations have employed the transition path sampling MD approach coupled with quenching to ascertain the mechanism of transformation close to the coexistence temperature, which is more representative of laboratory conditions than conventional brute-force MD that involves excessive superheating to induce the transformation. The study reveals that on length scales below 10 nm the β → α transformation in DL-norleucine crystals occurs by a concerted layer displacement mechanism. This finding is significant since collective structural transitions could be the mechanisms of choice in molecular crystals with hydrogen-bonded layers or chains, which are considered to be particularly amenable to control and have the potential to form the basis for molecular machines that transform heat into mechanical work.
AB - A long-standing question is whether concerted molecular displacements can occur during first-order phase transformations in molecular crystals. We have investigated the molecular level mechanism of the temperature-induced β → α phase transition in the molecular crystal DL-norleucine using molecular dynamics (MD) simulations. The simulations have employed the transition path sampling MD approach coupled with quenching to ascertain the mechanism of transformation close to the coexistence temperature, which is more representative of laboratory conditions than conventional brute-force MD that involves excessive superheating to induce the transformation. The study reveals that on length scales below 10 nm the β → α transformation in DL-norleucine crystals occurs by a concerted layer displacement mechanism. This finding is significant since collective structural transitions could be the mechanisms of choice in molecular crystals with hydrogen-bonded layers or chains, which are considered to be particularly amenable to control and have the potential to form the basis for molecular machines that transform heat into mechanical work.
U2 - 10.1039/C3RA40653A
DO - 10.1039/C3RA40653A
M3 - Journal article
VL - 31
SP - 12810
EP - 12815
JO - RSC Advances
JF - RSC Advances
ER -