[en] The αarrow-right-leftß phase transition in AgI is studied with use of the new molecular-dynamics technique which allows for a dynamical variation of the shape and size of the cell. In the present model, upon heating of ß-AgI, the iodine ions undergo a hcp→bcc transformation and silver ions become mobile, whereas the reverse transformation is observed on cooling of α-AgI. The calculated αarrow-right-leftß transition temperature and structural and dynamical properties are in good agreement with experiments