Predicting the frequency dispersion of electronic hyperpolarizabilities on the basis of absorption data and thomas-kuhn sum rules

Successfully predicting the frequency dispersion of electronic hyperpolarizabilities is an unresolved challenge in materials science and electronic structure theory. We show that the generalized Thomas-Kuhn sum rules, combined with linear absorption data and measured hyperpolarizability at one or two frequencies, may be used to predict the entire frequency-dependent electronic hyperpolarizability spectrum. This treatment includes two- and three-level contributions that arise from the lowest two or three excited electronic state manifolds, enabling us to describe the unusual observed frequency dispersion of the dynamic hyperpolarizability in high oscillator strength M-PZn chromophores, where (porphinato)zinc(II) (PZn) and metal(II)polypyridyl (M) units are connected via an ethyne unit that aligns the high oscillator strength transition dipoles of these components in a head-to-tail arrangement. We show that some of these structures can possess very similar linear absorption spectra yet manifest dramatically different frequency dependent hyperpolarizabilities, because of three-level contributions that result from excited state-to excited state transition dipoles among charge polarized states. Importantly, this approach provides a quantitative scheme to use linear optical absorption spectra and very limited individual hyperpolarizability measurements to predict the entire frequency-dependent nonlinear optical response. Copyright © 2010 American Chemical Society.

[Book review] Reviews. Scarlett Thomas, PopCo, London and New York: Fourth Estate, 2004

Book review of: Scarlett Thomas, PopCo, London and New York: Fourth Estate, 2004. 1-84115-763-5, £12.99.

Thomas Koinzer: Auf der Suche nach der demokratischen Schule, Amerikafahrer, Kulturtransfer und Schulreform in der Bildungsreformära der Bundesrepublik Deutschland, Bad Heilbrunn: Klinkhardt 2011 [Rezension]

Rezension von: Thomas Koinzer: Auf der Suche nach der demokratischen Schule, Amerikafahrer, Kulturtransfer und Schulreform in der Bildungsreformära der Bundesrepublik Deutschland, Bad Heilbrunn: Klinkhardt 2011 (279 S.; ISBN 978-3-7815-1811-7; 32,00 EUR)

Occurrence of the physonect siphonophore Apolemia uvaria (Lesueur, 1815) off Plymouth and in south-west England

In September 2007, observations were made of a siphonophore in surface waters and near to the seabed by sea users off south Devon and south-east Cornwall. The same siphonophore was also recorded from regular samples collected offshore of Plymouth. The species is identified as Apolemia uvaria, which had not previously been recorded off Plymouth. It was sampled until March 2008 and re-appeared, in smaller numbers, in autumn 2008 until February 2009 but was not reliably reported in autumn 2009 (to end of October). The occurrence is unlikely to be due to sea warming, but more likely some variation in oceanic currents, possibly influxes of Atlantic water