IntroductionWe consider the Schrodinger operator H=H Q +V in the Hilbert space L\R n }, 72^1, where H 0 is the self -ad joint realization of -A in L\R n } and V is a symmetric operator with //o-bound less than one. This paper is mainly devoted to obtaining detailed informations about the asymptotic behavior in time of the following quantities:where (j)^L\R n ) is an appropriate initial datum. We obtained some new estimates for (l)-(3).For a nice initial datum 0, it is reasonable to expect that e~i tH^^Lp (R n ) for all t^R and that the map R^t^e~i tH^^Lp (R n ) is continuous even when p^2. By taking the asymptotic behavior of the Schrodinger free evolution group into account, it is natural to think that for scattering solutions (i.e., e~U H (f> with 0 orthogonal to any eigenvector of H\ (l)-(3) decay as £->±oo provided 2