Convolution  approximation for swift Particles

CasP version 6.0  (March 2021),   ©2001-2021 freeware

The CasP program is freeware. It may be copied and distributed only along with all the additional resource files of this package and only without fee. There is no restriction on the number of copies and on the recipients. Any publications, however, that make use of UCA or PCA results or other results of this program should be accompanied by proper references to the last work from the list of publications .

Energy Transfers and Stopping Power

In CasP fast numerical calculations of the mean electronic energy transfer Q_e (due to excitation and ionization of target atoms) are performed for each individual impact parameter b in a collision. The total electronic energy-loss cross-section S_e (equivalent to the stopping power) is subsequently calculated from Q_e(b). The computation of Q_e and S_e accounts for a selected predefined projectile-screening function. By selecting a proper screening function, it is possible to treat non-equilibrium energy-loss phenomena. Furthermore, the unitary convolution approximation UCA (default selection) is a non-linear theory, as it includes the Bloch terms. Therefore, even for bare projectiles, the results do not scale with the square of the projectile charge (as most other quantum theories do).

Publications and citation

Detailed information on the present PCA and UCA models may be found in publications

Please cite the latest references and give the type of model ("UCA" is the default value) and the screening function ("charge-state scan” is the default value), when using results of CasP.

Additional information may be obtained from the file "ReadMe.txt", supplied with CasP.