There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Photoinduced motions in azo-containing polymers.

How Proteins Trigger Excitation Energy Transfer in the FMO Complex of Green Sulfur Bacteria

Discotic Liquid Crystals.

The generalized Langevin equation describes processes in a mechanical system with both deterministic and random forces which have comparable magnitudes (i.e., neither the deterministic nor random part can be neglected) and the random force is a transformed white noise. Examples of such processes are well known in physics. In this chapter, we use integral operators with Riemannian parallel translation in order to study the Langevin equations arising in geometric mechanics. Note that in the case under consideration the trajectories of the process are a.s. smooth. This makes the analysis of such systems technically much simpler than that of the general ones studied in Chap. 4.

The Langevin Equation

The effect of azo-dye on some optical and thermodynamical properties of the liquid crystal 5CB are examined. The relation between molecular geometry of the guest, guest and host order parameters and nematic-isotropic transition temperature of the azo-dye/liquid crystal mixtures is determined. The experimental results are compared in some detail with calculations done on the basis of the molecular mean-field theory and predictions of the lattice models as well. It has been found that good agreement between experiment and theory can be obtained taking into account not only the molecular sizes of the solute and the guest-host interaction, but also the concentration dependence of the dye order parameter and the flexibility of the end-chain of the liquid crystal molecules.

The Study of the Guest Effect on the Nematic Phase Stabilization

Guest-host interactions in dichroic dye-liquid crystal mixtures in smectic A and nematic phases

Dichroism and polarized fluorescence of chlorophyll a, chlorophyll c and bacteriochlorophyll a dissolved in liquid crystals.

Langmuir films of members of two homologous series, the 4‐n‐alkyl‐4′‐cyanobiphenyls (nCB) for n = 2–14 and trans‐4‐n‐alkyl(4′‐cyanophenyl)cyclohexanes (PCHn) for n = 2–12, have been studied by recording surface pressure/area isotherms and by Brewster angle microscopy. It has been found that the compounds with very short chains (n3) and very long chains (n>12 for nCB, n>10 for PCHn) are unable to form compressible monolayers at the air–water interface. Other members of both series can form stable Langmuir films, but both their rigidity and stability as well as the molecular packing vary with the alkyl chain length. The isotherms and BAM images imply that the organization of the liquid crystal molecules in the films is to some extent correlated with their ability to form corresponding mesophase in the bulk: nematogenic compounds tend to form rounded droplet‐like domains, whereas smectogenic compounds tend to form flat domains.

Danuta Bauman

Papers

The Study of the Guest Effect on the Nematic Phase Stabilization

Guest-host interactions in dichroic dye-liquid crystal mixtures in smectic A and nematic phases

Dichroism and polarized fluorescence of chlorophyll a, chlorophyll c and bacteriochlorophyll a dissolved in liquid crystals.

Influence of the alkyl chain length of some mesogenic molecules on their Langmuir film formation ability

Spectral properties of fluorescent dyes in nematic liquid crystals