Lec 19 MIT 3.320 Atomistic Computer Modeling of Materials
GERBRAND CEDER: So what I want to do today is finish up Monte Carlo simulation and go into a little more advanced things in Monte Carlo simulation and then also go into free energy integrations and other coarse-graining methods so when direct simulation won't work. If you remember, I introduced Monte Carlo simulation as a way of importance sampling and contrasted it against simple sampling. What I want to show you today, there's actually quite a few things in between that, in some cases, can be practical. Remember the idea of simple sampling is that you sample randomly and then you weigh with a probability that's correct relatively, where the states have their correct relative probability to one another. Importance sampling is sampling with the correct probability and then just averaging the quantity you sample, but you can actually sample with things in between. So here you're sampling with a probability proportional to that exponential of that Hamiltonia...