Geometric Convergence and Central Limit Theorems for Multidimensional Hastings and Metropolis Algorithms by GO Roberts and RLTweedie Criteria for geometric convergence of multidimensional Hastings algorithms are given in terms of the tail behaviour, and the curvature of the contours of the target density. Conditions leading to non-geometric convergence are also given, and the results are then related to the existence of central limit theorems for moments of the Markov chain.