In chemistry, Dynamic Monte Carlo (DMC) is a method for modeling the dynamic behaviors of molecules by comparing the rates of individual steps with random numbers. Unlike the Metropolis Monte Carlo method, which has been employed to study systems at equilibrium, the DMC method is used to investigate nonequilibrium systems such as reaction, diffusion, etc. This method is mainly applied to analyze the behavior of adsorbates on surfaces.
There are several well-known methods for performing DMC simulations, including the First Reaction Method (FRM) and Random Selection Method (RSM). Although the FRM and RSM give the same results from a given model, the computer resources are different depending on the applied system.
In the FRM, the reaction whose time is minimum on the event list is advanced. In the event list, the tentative times for all possible reactions are stored. After the selection of one event, the system time is advanced to the reaction time, and the event list is recalculated. This method is efficient in computation time because the reaction always occurs in one event. On the other hand, it consumes a lot of computer memory because of the event list. Therefore, it is difficult to apply to large-scale systems.
The RSM decides whether the reaction of the selected molecule proceeds or not by comparing the transition probability with a random number. In this method, the reaction does not necessarily proceed in one event, so it needs a lot of computation time. However, this method saves computer memory because it does not use an event list. Large-scale systems are able to be calculated by this method.
MonteCarlomethods are methods for solving various kinds of computational problems by using random numbers (or more often pseudo-random numbers), as opposed to deterministic algorithms.
MonteCarlomethods are extremely important in computational physics and related applied fields, and have diverse applications from esoteric quantum chromodynamics calculations, to use by engineers in designing heat shields and aerodynamic forms.
MonteCarlo simulations are distinguished from other types of simulation techniques by their extensive use of random numbers and repeated trials.
MonteCarlomethods are extremely important in computational physics and related applied fields, and have diverse applications from esoteric quantum chromodynamics calculations to designing heat shields and aerodynamic forms.
MonteCarlomethods were central to the simulations required for the Manhattan Project, though were strongly limited by the computational tools at the time.
Uses of MonteCarlomethods require large amounts of random numbers, and it was their use that spurred the development of pseudorandom number generators, which were far quicker to use than the tables of random numbers which had been previously used for statistical sampling.