Bioluminescent Simulations

Questions
#1

I am brand new to Q-Chem, and not a code-person at all, so take this with the appropriate level of grace. I am designing a course for photobiology, and I know that TDDFT is a tool that is used for excited states and molecular orbitals (one that I will learn to use in time). I am wondering whether there is a workflow, however convoluted, to predict the energy gap b/t HOMO and LUMO as a reaction proceeds, which would identify the point where a chemiluminescent/bioluminescent reaction will intersect and help approximate the emission.

Some problems/constraints:
-I want students to do this by selecting a luminophore, inserting the substrate and product (and hopefully but maybe not always the excited state) into Q-Chem, and generating a reaction curve for S0 and S1. That means they will not have a measurement of energy going in other than what is available for those three structures in literature or generated by Q-Chem.
-I do not need a continuous curve, but I’d need more that just the three points.
-It would be a miracle if it clearly identified the light as an emission spectrum, but I intend for students to be able to make that prediction based on energy gap alone.
-Environment affects would be hard to find from literature anyways, but would affect the results if they were able to be applied.

Thank you for whatever insight you can provide, even if the answer is no.
Best,
Aidan

#2

Sure, it sounds like this is all feasible, you can easily get HOMO and LUMO energies and S1-S0 excitation gap at any sequence of geometries. (You should note that HOMO-LUMO gap is not the same as S1-S0 gap; the latter is well-defined but LUMO energy is not always, although can still sometimes afford useful information.) It’s not quite clear what “reaction curve” you have in mind but if you can come up with a way to define a set of structures then this workflow makes sense. There are dielectric solvation models for TD-DFT available, as a simple means to test the effect of environment.