Astronomers have constructed models of globular clusters for over 100 years. These models mainly fall into two categories: (i) static models, such as King's model and its variants, and (ii) evolutionary models. Most attention has been given to static models, which are used to estimate mass-to-light ratios and mass segregation, and to combine data from proper motions and radial velocities. Evolutionary models have been developed for a few objects using the gaseous model, the Fokker-Planck model, Monte Carlo models and N-body models. These models have had a significant role in the search for massive black holes in globular clusters, for example.

In this presentation the problems associated with these various techniques will be summarised, and then we shall describe new work with Giersz's Monte Carlo code, which has been enhanced recently to include the stellar evolution of single and binary stars. We describe in particular recent attempts to model the nearby globular cluster M4, including predictions on the spatial distribution of binary stars and their semi-major axis distribution, to illustrate the effects of about 12 Gyr of dynamical evolution. We also discuss work on an approximate way of predicting the “initial” conditions for such modelling.

Abundance variations in globular clusters have been observed for the light elements C, N, O, Na, Al, as well as sometimes Mg. Such variations can be understood as the result of H-burning. In particular for the globular cluster M4, anticorrelations of O with Na and Al have been established from previous studies. In this study, we discuss fluorine abundances in a sample of M4 red-giants derived from infrared high-resolution spectra obtained with Pheonix on Gemini South. Our results show that fluorine now can be added to the suite of elements that are shown to vary in M4: the abundance of 19F is found to be anti-correlated with the sodium and aluminium variations. These results provide further evidence that H-burning is indeed responsible for the observed chemical inhomegeneities. Moreover, from comparisons with stellar models, tighter constraints on the mass of the polluting star in this globular cluster are extablished.