conducted a UV-vis spectra for caffeine/PVA films. I got two peaks at about 203nm and 272nm. I think that those are related to the imino group of the imidazole ring and the carbonyl group, respectively. Also, the associated transitions are pi to pi* and n to pi*, respectively. Can you help me verifying that?.  One more question, 203nm peak experiments a bathochromic shift at higher caffeine concentrations... is that mean an increase in conjugation due to the addition of more axochromic molecules? or what is a better description for that shift. It has something to do with the PVA matrix?

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Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
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I conducted a UV-vis spectra for caffeine/PVA films. I got two peaks at about 203nm and 272nm. I think that those are related to the imino group of the imidazole ring and the carbonyl group, respectively. Also, the associated transitions are pi to pi* and n to pi*, respectively. Can you help me verifying that?. 

One more question, 203nm peak experiments a bathochromic shift at higher caffeine concentrations... is that mean an increase in conjugation due to the addition of more axochromic molecules? or what is a better description for that shift. It has something to do with the PVA matrix?

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