  In this paper, we study dynamics of geodesic flows over closed surfaces of
genus greater than or equal to 2 without focal points. Especially, we prove
that there is a large class of potentials having unique equilibrium states,
including scalar multiples of the geometric potential, provided the scalar is
less than 1. Moreover, we discuss ergodic properties of these unique
equilibrium states. We show these unique equilibrium states are Bernoulli, and
weighted regular periodic orbits are equidistributed relative to these unique
equilibrium states.
