[passingbyenthusiast]

Doing some lab work over the summer, and I have collected a lot of UV-vis graphs of a particular compound deposited on thin films on quartz substrates. (can't reveal the compound here sorry)

However I'm not really sure how to interpret the graphs in order to ascertain the molecular structure or packing.

For example I get two different UV-vis spectrums of the same compound if I anneal the thin film at 100°C, and don't anneal it. Like there is a clear redshift in the peaks of the spectrum. Other than that, I really don't know how to explain why that redshift happened and the wavelength changed.

My mentor has just told me to look at journal papers but they don't explain what is happening other than the usual n-pi* or pi-pi* transitions, which really is just a theoretical treatise.

So yeah, in general how do I interpret UV-vis graphs of unknown compounds, in particular the molecular structure and packing orientation?

[Corribus]

There's no easy way to address this question generally, because energetic shifts can be caused by so many things. You have to consider the data on a case-by-case basis. If you supplied more detail about chemical structure and the experimental methods, then maybe I could give you some guidance.

[wildfyr]

Is your boss referring to H and J aggregation perhaps?