title: Structures of chiral smectic-C mesophases revealed by polarization-analyzed resonant x-ray scattering.
abstract: We report polarization-analyzed, resonant x-ray diffraction at the sulfur K edge performed upon free-standing liquid-crystal films. Our studies of the thiobenzoate liquid-crystal enantiomer 10OTBBB1M7 yield the polarization states of resonant satellite peaks arising from characteristic superlattices in the chiral smectic-C (SmC(*)) variant phases, including the antiferroelectric SmC(*)(A), ferrielectric SmC(*)(FI1) and SmC(*)(FI2), as well as SmC(*)(alpha). The observed polarizations agree with the clock model of chiral smectic-C variants, and rule out other proposals made to date for these structures. Data from the 10OTBBB1M7 racemate also support the clock model. Our resonant diffraction results from a thiophene liquid-crystal compound reveal the same superlattice periodicities seen in corresponding antiferroelectric and ferrielectric phases of 10OTBBB1M7.
authors.affiliation: School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: P
authors.initials: P
authors.lastname: Mach
authors.forename: R
authors.initials: R
authors.lastname: Pindak
authors.forename: A M
authors.initials: AM
authors.lastname: Levelut
authors.forename: P
authors.initials: P
authors.lastname: Barois
authors.forename: H T
authors.initials: HT
authors.lastname: Nguyen
authors.forename: H
authors.initials: H
authors.lastname: Baltes
authors.forename: M
authors.initials: M
authors.lastname: Hird
authors.forename: K
authors.initials: K
authors.lastname: Toyne
authors.forename: A
authors.initials: A
authors.lastname: Seed
authors.forename: J W
authors.initials: JW
authors.lastname: Goodby
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
authors.forename: L
authors.initials: L
authors.lastname: Furenlid