Photochemical versus Photophysical

What is the difference between the terms photochemical and photophysical properties? What are some examples from each category?

• Reminds me about Differences between chemical physics and physical chemistry? – Martin - マーチン May 10 at 20:57
• So is it bonkers when I see a paper describing the photochemical and photophysical properties of X? – Hazinga May 11 at 1:07
• Just a guess: photophysical can mean anything relating to the interaction of light and matter, simple absorption for instance. Photochemical implies a chemical reaction results from the interaction due to formation of excited species. – Buck Thorn May 11 at 6:03
• In photochemistry light is used to break a bond e.g. $\ce{I_2 +light -> 2I\cdot}$ or trans stilbene + light $\to$ cis stilbene, photophysics is the study of how this happens. – porphyrin May 11 at 7:09
• Photophysics digs a lot into details. They can be or not associated to a following reaction. While absorption can be a analytical chemistry tool, and might be relevant to conduct photochemical reactions, doing time resolved spectroscopy is certainly photophysics. I think that the comment by Buck Thorn helps in a sort of definition, but the point made by Martin is valid, too. In all cases, recording Absorption spectra, to give an example, certainly isn't photochemistry. Though is likely the most familiar physical technique among chemists. – Alchimista May 11 at 8:19