Structural Variants of RM734 in the Design of Splay Nematic Materials

Structural Variants of RM734 in the Design of Splay Nematic MaterialsThe recent discovery of the splay nematic phase, a new nematic polymorph that has been found to be both polar and ferroelectric, is the lead paragraph in an entirely new chapter in the history of liquid crystals. The potential for transformative applications utilizing this state of matter – such as photonics, non-linear optics, memory applications and so on - can only be met with significant improvements in the temperature range of existing materials such as 4-(4-nitrophenoxycarbonyl)phenyl 4-methoxy-2-methoxybenzoate (RM734). Herein we present several families of materials which are structurally related to the archetypal new nematic material, RM734, including the first non-rod-like materials within the context of the splay nematic phase. We find that the incidence (or absence) of this new nematic variant in a designer material cannot be easily rationalized in terms of molecular dipole moment or polarizability. However, mixture formulation shows promise for the engineering of materials with improved working temperature ranges.

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Structural Variants of RM734 in the Design of Splay Nematic Materials

10.26434/chemrxiv.14269916.v1 ◽

2021 ◽

Author(s):

Richard Mandle ◽

Stephen Cowling ◽

John W. Goodby

Keyword(s):

Nematic Phase ◽

Linear Optics ◽

Structural Variants ◽

Molecular Dipole ◽

Non Linear Optics ◽

Working Temperature ◽

Temperature Ranges ◽

History Of ◽

State Of Matter ◽

Memory Applications

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A Unified Mathematical Formalism for First to Third Order Dielectric Response of Matter: Application to Surface-Specific Two-Colour Vibrational Optical Spectroscopy

Symmetry ◽

10.3390/sym13010153 ◽

2021 ◽

Vol 13 (1) ◽

pp. 153 ◽

Cited By ~ 1

Author(s):

Christophe Humbert ◽

Thomas Noblet

Keyword(s):

Dielectric Response ◽

Structure And Properties ◽

Linear Optics ◽

Third Order ◽

Mathematical Functions ◽

Sum Frequency ◽

Non Linear Optics ◽

Non Linear ◽

Light Excitation

To take advantage of the singular properties of matter, as well as to characterize it, we need to interact with it. The role of optical spectroscopies is to enable us to demonstrate the existence of physical objects by observing their response to light excitation. The ability of spectroscopy to reveal the structure and properties of matter then relies on mathematical functions called optical (or dielectric) response functions. Technically, these are tensor Green’s functions, and not scalar functions. The complexity of this tensor formalism sometimes leads to confusion within some articles and books. Here, we do clarify this formalism by introducing the physical foundations of linear and non-linear spectroscopies as simple and rigorous as possible. We dwell on both the mathematical and experimental aspects, examining extinction, infrared, Raman and sum-frequency generation spectroscopies. In this review, we thus give a personal presentation with the aim of offering the reader a coherent vision of linear and non-linear optics, and to remove the ambiguities that we have encountered in reference books and articles.

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