A simple construction procedure of absorbing potentials

A simple procedure to construct absorbing potentials is provided. It is based on adding a series of equal length complex square barriers and optimizing their real and imaginary parts to achieve maximum absorption at a selected set of momenta. The method is flexible, robust, and easy to apply. The absorption widths obtained are better than other known functional forms for the important low momentum region. A comparison is made with parameters used for an H+H2 collinear collision.