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Various modern electronic structure methods are now days used to teach computational chemistry to undergraduate students. Such quantum calculations can now be easily used even for large size molecules.

The haem pigment of Porphyromonas gingivalis is composed of [micro]-oxo bishaem, [[Fe(III)PPIX].sub.2]O, but the nature of that generated by Prevotella species has not been established. Mossbauer, Raman and UV-visible spectrophotometry were used to characterize the haem pigment of Prevotella intermedia and Prevotella nigrescens. M6ssbauer and Raman spectroscopy revealed the major haem species to be monomeric iron protoporphyrin IX, Fe(III)PPIX.OH (haematin). The terminal growth pH of both species on blood agar was between 5.8 and 6.0, which favours the formation and maintenance of monomeric Fe(III)PPIX.OH. Incubation of Pr. nigrescens and Pr. intermedia with oxyhaemoglobin at pH 6.5 resulted in formation of aquomethaemoglobin which was degraded to generate Fe(III) PPIX.OH which in turn became cell-associated, whilst incubation at pH 7*5 resulted in formation of [[Fe(III)PPIX].sub.2]O. It is concluded that both Prevotella species degrade oxyhaemoglobin to form [[Fe(III)PPIX].sub.2]O as an intermediate, which is converted to Fe(III)PPIX.OH through a depression in pH. The low pH encourages cell-surface deposition of insoluble Fe(III)PPIX.OH which would act as a barrier against oxygen and reactive oxygen species, and also protect against [H.sub.2][O.sub.2] through its inherent catalase activity.

The effect on addition of europium in the formation of the different structures and the usefulness of the various polymorphs as phosphors is reported. The results indicated that the multiple sites observed for the europium in the calcined samples result from the europium doping into both the anatase and the brookite contaminant lattice, which is responsible for the luminescence in the metastable crystalline titania.

Se solid-state NMR spectra with cross-polarization and magic-angle spinning on (M(Se4)(sub 2))(super 2-) complexes with (Me(sub 4)N)+ and (Et(sub 4)N)+ facilitate the calculation of main constituents of Se77 shielding tensor from spinning sideband intensities. Structural changes in the (M(Se4)(sub 2))(super 2) geometry with cations between (Et4N)+ and (Me4N)+ complexes manifest in Se(77) isotropic chemical shifts.

This article reviews the origin, use and history of indigo, woad and Tyrian Purple, which are among the most ancient of dyes. The emphasis is on the chemistry of the production and syntheses of the dyes, together with some reference to the use of their spectroscopic properties as an aid to their identification in artefacts.

When integrated with a microscope, Raman spectroscopy provides a uniquely specific and sensitive means of identifying pigment grains of sub-micrometre dimensions in a broad range of artefacts. This article reviews the methodology of Raman microscopy and its application to the study of mediaeval manuscripts.

The electronic and resonance Raman spectra of dirhodium tetrathiocarboxylate complexes are compared with those of their tetracetate analogues. A red (bathochromic) shift in the blue region and a lower wavenumber for the rhodium-rhodium stretching fundamental indicate longer and weaker Rh-Rh bonds for the tetrathiocarboxylate than for the tetraacetate complex. These results are consistent with earlier evidence from X-ray crystallographic studies.

Two spectroscopic techniques that are very sensitive to low concentration of activators in phosphor lattices are discussed. Mossbauer and laser Raman spectroscopy have benefited from considerable technological advances and these techniques are becoming increasingly user-friendly.