New types of complex motion of a simple camphor boat.

We discuss the motion of a rectangular camphor boat, considering the position of a camphor pill in relation to the boat's stern as the control parameter. The boat moves because the pill releases surface active molecules that decrease the surface tension and support the motion. We introduce a new experimental system in which the boat rotates on a long arm around the axis located at the centre of a Petri dish; thus, the motion is restricted to a circle and can be studied under stationary conditions for a long time.

Magnetic Circular Dichroism of -Phenyl-Substituted Pd-Octaethylporphyrins.

Absorption and magnetic circular dichroism (MCD) spectra have been measured and theoretically simulated for a series of palladium octaethylporphyrins substituted at the positions with phenyl groups ( = 0-4). Analysis of the spectra included the perimeter model and time-dependent density functional theory (TDDFT) calculations. With the increasing number of phenyl substituents, the molecule is transformed from a positive hard (ΔHOMO > ΔLUMO) to a soft (ΔHOMO ≈ ΔLUMO) chromophore.

Detection of a weak ring current in a nonaromatic porphyrin nanoring using magnetic circular dichroism.

We compare the absorption and magnetic circular dichroism (MCD) spectra of a series of porphyrin oligomers - dimer, tetramer, and hexamer - bound in a linear or cyclic fashion. The MCD signal is extremely weak for low energy transitions in the linear oligomers, but it is amplified when the cyclic porphyrin hexamer binds a template, restricting rotational freedom. The appearance of Faraday A terms in the MCD spectra demonstrates the presence of a magnetic moment, and thus, uncompensated electronic current.

A new algorithm for identification of components in a mixture: application to Raman spectra of solid amino acids.

The procedure for identifying components in a mixture was developed and tested on Raman spectra of mixtures of solid amino acids, using the spectra of single amino acids as templates. The method is based on finding the optimum scaling coefficients of the linear combination of template spectra that minimize the Canberra distance between measured and reconstructed spectra. The Canberra distance, used here as a measure of dissimilarity between spectra, defines the non-convex objective function in the related optimization process.