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 Disclinations (2)
 Liquid Crystals (2)
 Light Scattering (2)
 Interface (2)
 Model (2)

 Energy (2)
 Heat Capacity (1)
 Field (1)
 Strength (1)
 Induced Orientational Order (1)
 Tricritical Point (1)
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 Octylcyanobiphenyl 8Cb (1)
 Orientational Order (1)
 Transition (1)
 Nematics (1)
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 Octyloxycyanobiphenyl (1)
 Smectic A Transition (1)
Articles 1  13 of 13
FullText Articles in Physics
CriticalBehavior At The Nematic To SmecticA Transition In A Nonpolar LiquidCrystal With Wide Nematic Range, Li Chen, J. D. Brock, J. Huang, Satyendra Kumar
CriticalBehavior At The Nematic To SmecticA Transition In A Nonpolar LiquidCrystal With Wide Nematic Range, Li Chen, J. D. Brock, J. Huang, Satyendra Kumar
Physics Publications
Highresolution xray scattering experiments to study the critical smecticA fluctuations in the nematic phase have been performed on a mixture of two nonpolar, twobenzenering compounds. The ratio T(NA)/T(NI) (= 0.885) for this mixture is much smaller than for previously studied similar materials. The smectic correlation lengths parallel and perpendicular to the smecticlayer normal are found to diverge anisotropically with characteristic exponentsnu parallelto = 0.75 +/ 0.03, nu perpendicularto = 0.65 +/ 0.03, and the susceptibility with gamma = 1.24 +/ 0.05.
Determination Of The LiquidCrystal Surface ElasticConstant K24, David W. Allender, G. P. Crawford, J. W. Doane
Determination Of The LiquidCrystal Surface ElasticConstant K24, David W. Allender, G. P. Crawford, J. W. Doane
Physics Publications
Analysis of the Frank free energy for nematics confined to cylindrical regions indicates that the director pattern is dependent on the surface elastic constant K_{24} if there is weak normal anchoring and escape along the cylinder axis. Using deuterium nuclearmagneticresonance techniques on samples of submicrometersize cavities in Nuclepore membranes, we report the first measurement of K_{24}.
Finite Molecular Anchoring In The EscapedRadial Nematic Configuration: A 2HNmr Study, G. P. Crawford, David W. Allender, J. William Doane, M. Vilfan, I. Vilfan
Finite Molecular Anchoring In The EscapedRadial Nematic Configuration: A 2HNmr Study, G. P. Crawford, David W. Allender, J. William Doane, M. Vilfan, I. Vilfan
Physics Publications
The directorfield configuration of a nematic liquid crystal confined to cylindrical cavities of polycarbonate Nuclepore membranes ranging from 0.3 to 0.05mum in radius is determined using deuterium nuclear magnetic resonance (H2 NMR). Spectral patterns from cavities of radius 0.3mum reveal the escapedradial configuration with singular point defects, but as the cylinder size is decreased, the elastic energy imposed by the curvature of the confining walls competes with the anchoring energy to tilt the directors away from their preferred perpendicular anchoring direction, preventing the expected transition to the planarradial configuration. A surface fitting parameter is directly determined by ...
Absence Of The Incommensurate SmecticA Phase In Db7ocn+8ocb Mixtures, Satyendra Kumar, Li Chien, V. Surendranath
Absence Of The Incommensurate SmecticA Phase In Db7ocn+8ocb Mixtures, Satyendra Kumar, Li Chien, V. Surendranath
Physics Publications
The results of a highresolution xraydiffraction study of the smectic phases in mixtures of DB_{7}OCN and 8OCB show that the incommensurate smecticA_{i2} phase, previously reported in this mixture, is in fact a coexistence of the partially bilayer smecticA_{d} and the bilayer smecticA_{2}phases at a firstorder phase transition between them.
NematicIsotropic PhaseTransition In A LiquidCrystal Droplet, S. Kralj, S. Zumer, David W. Allender
NematicIsotropic PhaseTransition In A LiquidCrystal Droplet, S. Kralj, S. Zumer, David W. Allender
Physics Publications
Possible phases in a nematic liquid crystal confined to a spherical submicrometer droplet embedded in a solid polymer are analyzed in terms of a Landaude Gennes theory. For a droplet with a radial structure we show that the strength of the nematicpolymer interfacial interaction affects the nematicparanematic (partially ordered isotropic phase) phase transition and may in addition induce a boundarylayer nematic phase. This boundary layer phase exists only in a narrow (approximately 0.1 K) temperature interval above the nematic phase for a restricted range of interfacial interactions. Also in the radial structure the degree of ordering is suppressed close ...
Microcalorimetric Study Of NematicToNeatSoap And NematicToIsotropic Phase Transitions In A Lyotropic Liquid Crystal, T. S. Shin, Satyendra Kumar
Microcalorimetric Study Of NematicToNeatSoap And NematicToIsotropic Phase Transitions In A Lyotropic Liquid Crystal, T. S. Shin, Satyendra Kumar
Physics Publications
The results of specificheat measurements at the nematic (N) toneatsoap (NS) and nematictoisotropic (I) phase transitions in binary mixtures of cesiumperfluorooctanoate and water are reported. The ratio of specificheat amplitudes above and below the NNS transition, A+/A, and the specificheat exponent α remain ∼1.0 and ≤0.02, respectively, suggesting 3D XYtype behavior. At the firstorder NI transition, vanishing latent heat and coexistence range at low concentration indicate the existence of a Landau point.
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom I: The Wavefunctions, R. A. Swainson, Gordon W. F. Drake
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom I: The Wavefunctions, R. A. Swainson, Gordon W. F. Drake
Physics Publications
In this and the following two papers in this series it is shown how the radial part of nonrelativistic and relativistic hydrogenic boundstate calculations involving the Green functions can be presented in a unified manner. The angular part of such calculations, being well understood, is performed in the standard way. In this, the first paper, it is shown how a suitable linear transformation of the two relativistic radial wavefunctions allows the pair of relativistic coupled differential equations to be written as two uncoupled secondorder equations which are simple generalizations of the corresponding nonrelativistic equation. This transformation is presented in a ...
Quantum Defects And The 1/N Dependence Of Rydberg Energies: SecondOrder Polarization Effects, Gordon W. F. Drake, R. A. Swainson
Quantum Defects And The 1/N Dependence Of Rydberg Energies: SecondOrder Polarization Effects, Gordon W. F. Drake, R. A. Swainson
Physics Publications
The principal result of this paper is a general expression for the secondorder dipole polarization energy of a Rydberg electron resulting from the term 1/r4 in the asymptotic potential, where 1 is the core polarizability. It is shown that the secondorder term contributes even as well as odd powers of 1/n in a 1/n expansion of the energies for Rydberg states. The results are used to extend the interpretation of the terms in a quantumdefect expansion. It is shown that the Ritz expansion for the quantum defect, which contains only even inverse powers of the effective quantum ...
Variational Calculation For The Ground State Of Lithium And The Qed Corrections For LiLike Ions, D. K. Mckenzie, Gordon W. F. Drake
Variational Calculation For The Ground State Of Lithium And The Qed Corrections For LiLike Ions, D. K. Mckenzie, Gordon W. F. Drake
Physics Publications
Highprecision variational calculations using multiple basis sets in Hylleraas coordinates are presented for the 1s22s 2S state of lithium. The variational bound of 7.478 060 326(10) a.u. for the nonrelativistic energy is in good agreement with our revised experimental value of 7.47 806 034(20) a.u., thereby resolving a longstanding disrepancy. Twoelectron calculations of the QED corrections are extended to threeelectron systems and compared with other results. The comparison for Lilike ions up to U89+ suggests a simple interpretation for the ''screening of the Lamb shift'' recently calculated by Cheng, Johnson, and Sapirstein [Phys. Rev ...
Erratum: Expectation Values Of Rp For Arbitrary Hydrogenic States (Physical Review A (1991) 43, 11, (6432)), Gordon W. F. Drake, R. A. Swainson
Erratum: Expectation Values Of Rp For Arbitrary Hydrogenic States (Physical Review A (1991) 43, 11, (6432)), Gordon W. F. Drake, R. A. Swainson
Physics Publications
No abstract provided.
Measurement Of The N=2 Lamb Shift In He+ By The Anisotropy Method, A. Van Wijngaarden, J. Kwela, Gordon W. F. Drake
Measurement Of The N=2 Lamb Shift In He+ By The Anisotropy Method, A. Van Wijngaarden, J. Kwela, Gordon W. F. Drake
Physics Publications
A highprecision measurement of the 2s 2S1/22p 2P1/2 Lamb shift in He+ by the quenchinganisotropy method is reported. The theory and experimental method are described in detail. The measured value of 14042.520.16 MHz (11 parts per million) rivals the accuracy of Lambshift measurements in hydrogen by microwave resonance. By subtracting the known loworder terms in the Lamb shift, we interpret the results as a measurement of the order (Z)6mc2 and higher contributions to the electron selfenergy GSE(Z). The various contributions to the Lamb shift are discussed, and a revised value for GSE(Z) at ...
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom Ii: The Green Functions, R. A. Swainson, Gordon W. F. Drake
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom Ii: The Green Functions, R. A. Swainson, Gordon W. F. Drake
Physics Publications
This is the second in a series of three papers in which it is shown how the radial part of nonrelativistic and relativistic hydrogenic boundstate calculations involving the Green functions can be presented in a unified manner. In this paper the nonrelativistic Green function is examined in detail; new functional forms are presented and a clear mathematical progression is shown to link these and most other known forms. A linear transformation of the four radial parts of the relativistic Green function is given which allows for the presentation of this function as a simple generalization of the nonrelativistic Green function ...
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom: Iii. The Reduced Green Functions, R. A. Swainson, Gordon W. F. Drake
A Unified Treatment Of The NonRelativistic And Relativistic Hydrogen Atom: Iii. The Reduced Green Functions, R. A. Swainson, Gordon W. F. Drake
Physics Publications
The last in a series of three papers in which it is shown how the radial part of nonrelativistic and relativistic hydrogenic boundstate calculations involving the Green functions can be presented in a unified manner. The work presented here is concerned with the reduced Green functions which arise in secondorder stationary state perturbation theory. Using a simple linear transformation of the four radial parts of the relativistic reduced Green function it is shown how the nonrelativistic and relativistic functions are special instances of the solution of a general secondorder differential equation. The general solution of this equation is exhibited in ...