I am running a quantum mechanical simulation on Psi4 for a certain number of monomers to generate data for a database. Some of these monomers are short, while some are long.
At the moment, I am generating .pdb files for these monomers using their SMILES string, and using OpenBabel's genetic algorithm to generate possible optimal conformers to use for my simulation.
Now obviously, if I could, I would generate as many conformers as possible for my monomers and throw them in Psi4 to generate all-encompassing data for them. However, since these computations are expensive, I can't do that and I have to budget my computational resources.
My idea is that the smaller monomers would require a smaller number of conformers to accurately depict their properties (50-100), while the larger monomers, having more degrees of freedom , would need more conformers to depict their properties.
I want to figure out a way to ballpark how many conformers do I need to evaluate for each monomer. How would you go about finding an estimate?
For example, say you had something small, like isoprene, and something larger, like benzyl methacrylate. How many conformers would you make for each of them? Is there a combinatorial argument you can make regarding torsional strains (or something) that you can use to get an estimate?
Any advice you have would be appreciated.