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Physical Sciences and Mathematics Commons

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Full-Text Articles in Physical Sciences and Mathematics

Synthesis And Protection Of Nitrogen Containing Heterocycles, Timothy I. Elwell May 1997

Synthesis And Protection Of Nitrogen Containing Heterocycles, Timothy I. Elwell

Undergraduate Honors Capstone Projects

The pyrrolo[2,3-d] pyrimidine ring systems are present in a variety of antibacterial/anticancer compounds. A scarcity of natural sources has made necessary the need for researchers to find more efficient methodologies to synthesize such compounds.1 The Edstrom research group is currently exploring new routes to these compounds, varying the protecting groups and the precursors used to make them.


Photothermal Lens Spectrometry Of Homogeneous Fluids With Incoherent White‐Light Excitationusing A Cylindrical Sample Cell, Agnes Chartier, Stephen E. Bialkowski Jan 1997

Photothermal Lens Spectrometry Of Homogeneous Fluids With Incoherent White‐Light Excitationusing A Cylindrical Sample Cell, Agnes Chartier, Stephen E. Bialkowski

Stephen E. Bialkowski

A model for photothermal lens signal generation in a cylindrical sample cell under constant irradiance excitation is described and tested. The model is developed with and without the assumption that the sample cell does not change temperature over the irradiation time. In both cases, the photothermal lens is predicted to be parabolic in form with a strength that is independent of sample cell radius. The predicted irradiance independence suggests that incoherent illumination can be used to perform photothermal lens spectroscopy in low-volume cells. Experimental evidence is obtained using a Xe arc lamp to perform photothermal lens spectroscopy in a 6 …


Diffraction Effects In Single‐ And Two‐Laser Photothermal Lens Spectroscopy, Stephen E. Bialkowski, Agnes Chartier Jan 1997

Diffraction Effects In Single‐ And Two‐Laser Photothermal Lens Spectroscopy, Stephen E. Bialkowski, Agnes Chartier

Stephen E. Bialkowski

A simple method for calculating the effects of optical geometry on photothermal lens signals is shown. This method is based on calculating cumulative electric-field phase shifts produced by a series of Gaussian refractive-index perturbations produced by the photothermal effect. Theoretical results are found for both pulsed-laser and continuous Gaussian laser excitation sources and both single- and two-laser apparatuses commonly employed in photothermal lens spectroscopy. The effects of apparatus geometry on the resulting signal are shown. Analytical time-dependent signal results are found for small signals. Analytical pump–probe focus geometry results allow direct optimization for certain conditions. The calculations indicate that the …