Naslov
WHEN CRYSTAL BEHAVES LIKE AN ACROBATE: THE XRPD AND DFT STUDY OF N'-2-PROPYLIDENE-4-HYDROXYBENZOHYDRAZIDE

Autori
Popović, Jasminka ; Skoko, Željko ; Despoja, Vito ; Lončarić, Ivor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts 23rd Conference of the Serbian Crystallographic Society / - , 2016, 29-29

Skup
23rd Conference of the Serbian Crystallographic Society

Mjesto i datum
Andrevlje, Srbija, 08.06.2016. - 12.06.2016

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
thermosalient effect, topotactic phase transition, crystal structure
(Thermosalient effect, topotactic phase transition, crystal structureotactic phase transition, crystal structure)

Sažetak
Thermosalient crystals are the next hot thing – very promising converters of thermal en- ergy into mechanical work on the nanoscale. These materials, when heated or cooled, un- dergo a sudden and sharp topotactic phase transition. During the transition, the crystals experience a change in their shape, as well as in the size of the unit-cell, that is so energetic that crystals literally jump off the stage to distances several times bigger than their dimen- sions [1]. It was reported [2] that N'-2-propylidene-4-hydroxybenzohydrazide exhibits three polymorphic modifications (I, II and III), all having the same polar space group Pna21 with the phase transitions I II being thermosalient. Our experiments showed that reversible III ↔II phase transition is characterized by thermosalient effect as well. We performed detailed structural (high temperature in-situ XRPD) and theoretical (DFT) study in order to explain jumping phenomenon in this system (Fig. 1). Large unit cells of the crystal usually prohibit the use of high-level quantum chemistry calculations, however, with the recent progress in development of density functional theory (DFT) with the van der Waals (vdW) interactions, good accuracy and predictability in modeling of molecular crystals has become accessible. Of several vdW implementations in DFT, we choose none- mipirical vdW-DF-cx functional for phonon calculations which provided an insight into the temperature dependence of a free energy of each polymorphic phase.

Izvorni jezik
Engleski

Znanstvena područja
Arheologija

POVEZANOST RADA