Maybe not the answer you expect, but a sufficiently ab-initio simulation is not something our current knowledge of chemistry permits! You could approach your pr

Maybe not the answer you expect, but a sufficiently ab-initio simulation is not something our current knowledge of chemistry permits! You could approach your problem with various degrees of approximation. Personally, I'm optimistic that we may make great progress in this area in the coming years, decades, and centuries. It's traditionally described as a lack of computing power, but I'm guessing there's a fair chunk of knowledge yet undiscovered that could help.