Grid-based dynamic electronic publication: A case study using combined experiment and simulation studies of crown ethers at the air/water interface.
Esther R Rousay, Hongchen Fu, Jamie M Robinson, Jeremy G Frey, Jonathan W Essex
School of Chemistry, University of Southampton,
Highfield, Southampton, SO17 1BJ, UK

Abstract The Publication@Source Paradigm and Challenges Body Molecular Dynamics Simulations Comparisons and Conclusions Acknowledgements Appendix:The TriScapeRDF browser References Glossary Search
Case Study Crown ether molecules at the water/air interface Introduction Benzo-15-Crown-5 UV Spectrum of Benzo-15-Crown-5 Surface Tension Measurements Second Harmonic Generation SHG Isotherm SHG Isotherm .2 Polarisation Dependence Polarisation Dependance Analysis The molecular hyperpolarisability and molecular orientation The molecular hyperpolarisability and molecular orientation .2 Analysis

Second Harmonic Generation

The equipment needed for the SHG experiment is shown diagrammatically in figure 5.

Figure 5. SHG apparatus showing the control of the polarisation of the fundamental and harmonic waves

The SHG equipment is similar to that used in our recent studies20 The frequency doubled beam from a Q-switched Nd:YAG, (532 nm, 5 ns pulse width and 20 Hz repetition rate) impinges on the surface of the sample at 60o to the surface normal. The polarisation of the input beam is controlled by a half-wave plate and polariser and a yellow Schott filter removes any second harmonic signal generated by the optics, and beam is then focused onto the sample surface by a convex lens (f = 100 mm). The beam is reflected off the surface and passes through a re-collimating lens and analysing polariser. UG5 filters are used to block the fundamental and the SHG signal is focussed on to the slit of the monochromator, and detected by a UV PMT. The signal is processed using a SRS pre-amp and boxcar and captures with a National Instruments A/D card and recorded on a PC automatically entered into the ?raw data? database (MySQL) together with the relevant metadata. Environmental data on the room and the laser is also now recorded and logged.

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