title: A molecular "phase ordering" phase transition leading to a modulated aperiodic composite in n-heptane/urea.
abstract: n-Heptane/urea is an aperiodic inclusion compound in which the ratio of host and guest repeats along the channel axis is very close to unity and is found to have a constant value (0.981) from 280 K to 90 K. Below 280 K, two phase transitions are observed. The first (T(c1) = 145 K) is a ferroelastic phase transition that generates superstructure reflections for the host while leaving the guest with 1D order. The second (T(c2) = 130 K) is a "phase ordering" transition to a four-dimensional structure (P2(1)11(0βγ)) with pronounced host-guest intermodulation and a temperature dependent phase shift between guests in adjacent channels.
authors.affiliation: Institut de Physique de Rennes, UMR UR1-CNRS 6251, Université de Rennes 1, 35042 Rennes, France.
authors.forename: C
authors.initials: C
authors.lastname: Mariette
authors.forename: M
authors.initials: M
authors.lastname: Huard
authors.forename: P
authors.initials: P
authors.lastname: Rabiller
authors.forename: Shane M
authors.initials: SM
authors.lastname: Nichols
authors.forename: C
authors.initials: C
authors.lastname: Ecolivet
authors.forename: Ted
authors.initials: T
authors.lastname: Janssen
authors.forename: Keith E
authors.initials: KE
authors.lastname: Alquist
authors.forename: Mark D
authors.initials: MD
authors.lastname: Hollingsworth
authors.forename: B
authors.initials: B
authors.lastname: Toudic