Dichroic optical spectroscopies and theoretical modelling have been used to describe the structure of aggregates of porphyrins in their gels in terms of: (i) the formation of helicoidal structures, (ii) the sign of the handedness, (iii) their extent and degree of structural order, and (iv) the annealing of the structural defects.

Structural changes in nucleic acids in the premelting region (T < melting temperature, T(m)) play an important role in the biological activity of DNA at physiological temperature. In the present communication we report the use of an ultrafast molecular rotor as an extrinsic fluorescence sensor to monitor the structural changes in natural DNA at T < T(m), which could not be detected even by circ...

A spatially non-local response tensor description of linear chiral signals such as circular dichroism is developed. By working directly with the vector potential rather that the electric and magnetic fields, we recast the signals in terms of correlation functions of charge and current densities and avoid the tedious expansion in multipoles.

Combined magnetically induced circular dichroism and Faraday rotation of an atomic vapor are used to develop a variant of the dichroic atomic vapor laser lock that eliminates lock sensitivity to temperature fluctuations of the cell. Operating conditions that eliminate first-order sensitivity to temperature fluctuations can be determined by low-frequency temperature modulation. This temperature-...

In the recently proposed phenomenon, nuclear spin-induced circular dichroism (NSCD), collective magnetisation of nuclei induces circular dichroism in a light beam passing through a molecular sample. Here we present the first computational predictions of NSCD for fullerenes C60 and C70. We show that the NSCD signal is nucleus-specific, like in NMR spectroscopy. Thus, NSCD may provide a new and p...

Extrinsic or pseudo-chiral (meta)surfaces have an achiral structure, yet they can give rise to circular dichroism when the experiment itself becomes chiral. Although these surfaces are known to yield differences in reflected and transmitted circularly polarized light, the exact mechanism of the interaction has never been directly demonstrated. Here we present a comprehensive linear and nonlinea...

We have expanded our reference set of proteins used in the estimation of protein secondary structure by CD spectroscopy from 29 to 37 proteins by including 3 additional globular proteins with known X-ray structure and 5 denatured proteins. We have also modified the self-consistent method for analyzing protein CD spectra, SELCON3, by including a new selection criterion developed by W. C. Johnson...

Circular dichroism (CD) is widely used in the structural characterization and secondary structure determination of proteins. The vacuum UV region (below 190 nm), where charge-transfer transitions have an influence on the CD spectra, can be accessed using synchrotron radiation circular dichroism (SRCD) spectroscopy. Recently, charge-transfer transitions in a conformationally diverse set of dipep...

Thermal denaturation of chromatin is observed by simultaneously monitoring absorption and circular dichroism at 276 nm as functions of temperature. Either observation indicates that sheared chromatins shows less thermal stability than native chromatin. The temperature-dependent ellipticities at 276 nm of these chromatins show features not seen in the absorption curves: the ellipticity of unshea...