EN
Let A = -Δ + V be a Schrödinger operator on $ℝ^{d}$, d ≥ 3, where V is a nonnegative potential satisfying the reverse Hölder inequality with an exponent q > d/2. We say that f is an element of $H^{p}_{A}$ if the maximal function $sup_{t>0} |T_{t}f(x)|$ belongs to $L^{p}(ℝ^{d})$, where ${T_{t}}_{t>0}$ is the semigroup generated by -A. It is proved that for d/(d+1) < p ≤ 1 the space $H^{p}_{A}$ admits a special atomic decomposition.