  We present a new theoretical method to treat atom-rigid bender inelastic
collisions at the Close Coupling level (RBCC) in the space fixed frame. The
coupling between rotation and bending is treated exactly within the rigid
bender approximation and we obtain the cross section for the rotational
transition between levels belonging to different bending levels. The results of
this approach are compared with those obtained when using the rigid bender
averaged approximation (RBAA) introduced in our previous work dedicated to this
system. We discuss the validity of this approximation and of the previous
studies based on rigid linear HCN.
