A one-dimensional boson model with a periodic array of local potential
cos beta phi(nR) is studied by variational procedures on the basis of
a trial ground state in the form of a Gaussian wave functional. The r
enormalized local mass is calculated which exhibits two limiting behav
iors: the correlation length is much smaller or larger than the spacin
g between the potentials. The crossover between them is smooth. Possib
le applications to the Kondo lattice model are also discussed. [S0163-
1829(98)03616-9].