The theory of optical activity presented in an earlier paper has been applied to helical structures, obtaining a compact formula for the residue rotation [ m ' ] ^ . In particular, the theory has been applied to the a-helix, and this theory consists of two parts: firstly the calculation of the magnitude and orientation of the polarisability tensor ellipsoid of the peptide residue from the locat...

The dielectric properties of 12 kbp plasmid DNA have been measured as a function of temperature in the range 5 degrees C to 40 degrees C. Time domain reflectometry was used to obtain dielectric data over the frequency range from 200 kHz to 3 GHz. Values of the frequency dependent polarisability per DNA macromolecule have been determined from the measurements. Possible mechanisms that could acco...

In this article, a system of amyloid fibrils, based on the protein beta-lactoglobulin, is studied by transient electric birefringence. Single pulses of an electric field were applied to the solution, and the initial rise and subsequent decay of birefringence analysed. The decay takes place on a range of relaxation times, and therefore contains information about the length distribution of fibril...

Transparent and colourless ionic liquids with refractive index over 1.60 were synthesised by combining 1-benzyl-3-methylimidazolium or hexyltriphenylphosphonium cations with suitable anions. There is a positive relation between their refractive index and Kamlet-Taft parameters, especially dipolarity/polarisability, suggested as a potential parameter to design ionic liquids with high refractive ...

The optical dipole force from a singe focussed laser beam was used to study the role of laser-induced molecular alignment on the centre-of-mass motion of carbon disulphide molecules in a molecular beam. The translational, rotational and vibrational temperatures of the CS2 molecules were measured to be 3.4±0.2 K, 35±10 K and 250±14 K respectively. The velocity of the beam was measured to be 542±...

A semiclassical formulation for the term energy of a many-electron atom is presented which includes gross structure, fine structure, core polarisation and core penetration effects. A very simple model combining perturbed Keplerian orbits with the BohrSommerfeld-Wilson quantisation hypothesis yields an explicit formula which, in appropriate limits, reduces to the familiar core polarisability and...

Si1-xGexnanocrystals (NCs) of different composition and size were generated using the Molecular Dynamics (MD) method by minimizing NC’s total energy calculated using Tersoff’s empirical potential and applying rigid boundary conditions. The dynamical matrix of the relaxed NC was constructed and the NC phonon modes were calculated. The localisation of the principal (Si-Si, Si-Ge and Ge-Ge) modes ...

A modified CNDO/2 method was used to calculate the conformational energy surface of zwitterionic glycine in a simulated polarizable environment. While the calculated global minimum for the in vacuo glycine zwitterion corresponds to an eclipsed conformation, the allowance of even a small degree of environmental polarisability inverts the relative stabilities of the staggered and eclipsed forms. ...