  In this paper we give an explicit formula for level 1 vertex operators
related to $U_q(\widehat{sl}(n))$ as operators on the Fock spaces. We derive
also their commutation relations. As an applications we culculate the one point
functions of the one-dimensional spin chain associated with the vector
representation of $U_q(\widehat{sl}(n))$, thereby extending the recent work on
the staggered polarization of the $XXZ$-model.
