  We study resonances for the Schr\"odinger operators with quadratic or
sub-quadratic repulsive potential. In the present paper, we show the
non-existence of resonances in some complex neighborhood of a fixed energy by
employing schemes of Briet-Combes-Duclos and Hunziker and by introducing a
proper distortion based on, but slightly modified, positive commutator method
of Mourre.
