Interlayer structures of the chiral smectic liquid crystal phases revealed by resonant X-ray scattering.
The structures of the liquid crystalline chiral subphases exhibited by several materials containing either a selenium or sulphur atom have been investigated using a resonant x-ray scattering technique. This technique provides a unique structural probe for the ferroelectric, ferrielectric, antiferroelectric, and SmC(*)(alpha) phases. An analysis of the scattering features allows the structural models of the different subphases to be distinguished, in addition to providing a measurement of the helical pitch. This paper reports resonant scattering features in the antiferroelectric hexatic phase, the three- and four-layer intermediate phases, the antiferroelectric and ferroelectric phases and the SmC(*)(alpha) phase. The helicoidal pitch has been measured from the scattering peaks in the four-layer intermediate phase as well as in the antiferroelectric and ferroelectric phases. In the SmC(*)(alpha) phase, an investigation into the helical structure has revealed a pitch ranging from 5 to 54 layers in different materials. Further, a strong resonant scattering signal has been observed in mixtures of a selenium containing material with as much as 90% nonresonant material.
Hirst
L S
LS
Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
Watson
S J
SJ
Gleeson
H F
HF
Cluzeau
P
P
Barois
P
P
Pindak
R
R
Pitney
J
J
Cady
A
A
Johnson
P M
PM
Huang
C C
CC
Levelut
A-M
AM
Srajer
G
G
Pollmann
J
J
Caliebe
W
W
Seed
A
A
Herbert
M R
MR
Goodby
J W
JW
Hird
M
M