  We study the static and dynamic properties of bromine electrosorption onto
single-crystal silver (100) electrodes by Monte Carlo simulation. At room
temperature the system displays a second-order phase transition between a
low-coverage disordered phase at more negative electrode potentials and a
c(2x2) ordered phase with bromine coverage 1/2 at more positive potentials. We
explore the phase diagram and demonstrate that the broad shoulder observed in
room-temperature cyclic voltammograms is due to local fluctuations resembling
ordered phases with coverage 1/4 which exist in the model at much lower
temperatures. We construct a dynamic Monte Carlo algorithm using a thermally
activated stochastic barrier-hopping model for the microscopic dynamics. We use
this algorithm to study the phase ordering and disordering processes following
sudden potential steps between the disordered phase and the c(2x2) phase and to
study the sweep-rate dependence in simulated cyclic-voltammetry experiments.
