Treatment of Gamow States, Using Tempered Ultradistributions

In the present manuscript, and with the use of tempered ultradistributions, we extend analitically the pseudonorm of Gamow states as defined originally by T. Berggren. We define this pseudonorm for all states determined by the zeros of the Jost function for any short range potential. As a particular example we study the s-states corresponding to the square-well potential.