[photochemsyn]

Here's another head-spinning application of the concept of entropy, in quantum information theory:

https://www.cambridge.org/core/books/abs/quantum-information...

> "The first fundamental measure that we introduce is the von Neumman entropy. It is the quantum analog of the Shannon entropy, but it captures both classical and quantum uncertainty in a quantum state. The von Neumann entropy gives meaning to a notion of the information qubit. This notion is different from that of the physical qubit, which is the description of a quantum state in an electron or a photon. The information qubit is the fundamental quantum informational unit of measure, determining how much quantum information is in a quantum system."

Incidentally chem.libretexts.org, a collection of open-source chemistry textbooks, has a good overview of the physical-chemical applications. The site is kind of a mess but you'd want chapter 18.3:

https://chem.libretexts.org/Bookshelves/General_Chemistry/Ma...