Abstract
The orientational ordering in a system of dipolar molecules located on a trigonal lattice is studied in the eight-sublattices approximation. Our concrete example is SO2 molecules in β-hydroquinone clathrate. It is assumed that the molecules interact with each other via effective dipole-dipole interactions, and that the crystal field acting on those molecules is of the form WA = CCOS[ν(φ-δA)], where φ is a rotational angle and A is a sublattice number. If ν is an odd integer, we assume that δA may different for different A. The mean electric field which depends on the depolarization field is obtained. Various cases of C, ν, δA are investigated. Results are as follows: the possible dipole arrangement is antiferroelectric in all cases; the phase transition for ν = 2, 4, 5, 6 is of second order; if ν = 1, no disordered phase occurs; if ν = 3, the phase transition is weakly of first order excep for special cases; the C dependence of the transition temperature is weak unless ν = 2; δA chiefly determines the equilibrium direction. A comparison with experiment suggests that the low-temperature phase of SO2-β-hydroquinone has ν = 2 or 3, and that interactions between enclosed SO2 molecules other than dipole-dipole interactions may be also effective.
| Original language | English |
|---|---|
| Pages (from-to) | 1364-1370 |
| Number of pages | 7 |
| Journal | journal of the physical society of japan |
| Volume | 66 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Jan 1 1997 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
Cite this
Effects of a Crystal Field on the Orientational Phase Transition in a System of Dipoles : A Mean-Field Study of SO2-β-Hydroquinone Clathrate. / Imasaka, Tomoko; Hirokawa, Shoji.
In: journal of the physical society of japan, Vol. 66, No. 5, 01.01.1997, p. 1364-1370.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of a Crystal Field on the Orientational Phase Transition in a System of Dipoles
T2 - A Mean-Field Study of SO2-β-Hydroquinone Clathrate
AU - Imasaka, Tomoko
AU - Hirokawa, Shoji
PY - 1997/1/1
Y1 - 1997/1/1
N2 - The orientational ordering in a system of dipolar molecules located on a trigonal lattice is studied in the eight-sublattices approximation. Our concrete example is SO2 molecules in β-hydroquinone clathrate. It is assumed that the molecules interact with each other via effective dipole-dipole interactions, and that the crystal field acting on those molecules is of the form WA = CCOS[ν(φ-δA)], where φ is a rotational angle and A is a sublattice number. If ν is an odd integer, we assume that δA may different for different A. The mean electric field which depends on the depolarization field is obtained. Various cases of C, ν, δA are investigated. Results are as follows: the possible dipole arrangement is antiferroelectric in all cases; the phase transition for ν = 2, 4, 5, 6 is of second order; if ν = 1, no disordered phase occurs; if ν = 3, the phase transition is weakly of first order excep for special cases; the C dependence of the transition temperature is weak unless ν = 2; δA chiefly determines the equilibrium direction. A comparison with experiment suggests that the low-temperature phase of SO2-β-hydroquinone has ν = 2 or 3, and that interactions between enclosed SO2 molecules other than dipole-dipole interactions may be also effective.
AB - The orientational ordering in a system of dipolar molecules located on a trigonal lattice is studied in the eight-sublattices approximation. Our concrete example is SO2 molecules in β-hydroquinone clathrate. It is assumed that the molecules interact with each other via effective dipole-dipole interactions, and that the crystal field acting on those molecules is of the form WA = CCOS[ν(φ-δA)], where φ is a rotational angle and A is a sublattice number. If ν is an odd integer, we assume that δA may different for different A. The mean electric field which depends on the depolarization field is obtained. Various cases of C, ν, δA are investigated. Results are as follows: the possible dipole arrangement is antiferroelectric in all cases; the phase transition for ν = 2, 4, 5, 6 is of second order; if ν = 1, no disordered phase occurs; if ν = 3, the phase transition is weakly of first order excep for special cases; the C dependence of the transition temperature is weak unless ν = 2; δA chiefly determines the equilibrium direction. A comparison with experiment suggests that the low-temperature phase of SO2-β-hydroquinone has ν = 2 or 3, and that interactions between enclosed SO2 molecules other than dipole-dipole interactions may be also effective.
UR - http://www.scopus.com/inward/record.url?scp=0642303129&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0642303129&partnerID=8YFLogxK
U2 - 10.1143/JPSJ.66.1364
DO - 10.1143/JPSJ.66.1364
M3 - Article
AN - SCOPUS:0642303129
VL - 66
SP - 1364
EP - 1370
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 5
ER -