## MOLSCAT v. 14

### S-Matrix Save Tape Post-Processors

These codes are not routinely maintained and are generally provided "as is" and undocumented, although they often contain useful comment cards.

- State-to-state integral cross sections
- This self-contained FORTRAN program for state-to-state cross sections calculates integral cross sections from the saved S-matrices. It also provides a quick and convenient summary of the contents of a save tape. Current program does
**not**handle ITYP = 4, 8, or 9. - State-to-state differential cross sections
- This self-contained FORTRAN program for differential cross sections was modified in Jan 95 to handle close coupling as well as coupled states cases. Current implementation is somewhat limited and is restricted to collision types, ITYP = 1, 2, and 7; with minor modifications it should handle ITYP = 5, and 6.
**Note**: some bugs in this code were fixed 1 Aug 95; a faulty Associated Legendre polynomial routine was replaced 26 Sep 95.- Pressure broadening cross sections
- A FORTRAN program (including all required MOLSCAT subroutines) which calculates pressure broadening cross sections from a save tape is available. This can be particularly useful for generating additional cross sections (such as line coupling cross sections) which were not calculated in the initial run.
- Pressure broadening in vibrational bands is often well approximated by ignoring vibrational coupling, in which case molecular scattering calculations for rotational excitation can be done separately for each vibrational level. A FORTRAN program (including all required MOLSCAT routines) which processes the two resulting save tapes (one for each vibrational level) and calculates pressure broadening cross sections for the vibrational band is available.
- The above codes use the formalism of Ben-Reuven and Shafer & Gordon which predicts only a pressure broadened and shifted Lorentzian line. Velocity changing effects (Doppler broadening and Dicke narrowing) may be predicted with the Generalized Hess Method [Monchick & Hunter, J. Chem. Phys.
**85**, 713 (1986); Monchick, J. Chem. Phys.**101**, 5566 (1994)]. FORTRAN codes are available to calculate GHM cross sections from a single save tape or, for vibrational bands, from two save tapes, one for each vibrational level, analogous to the codes discussed above. Both of these programs require a common set of FORTRAN subroutines. Note that the usual Lorentzian width and shift cross sections are equivalent to one of the two (complex) GHM cross sections and are obtained automatically in the GHM calculation. Current code is limited to full close coupling cases only. - Senftleben-Beenakker effect cross sections.
- A FORTRAN program for SBE cross sections (including all required MOLSCAT subroutines) is available. It converts saved S-matrices to generalized phenomenological cross sections defined by Fitz, Kouri, Liu, McCourt, Evans, and Hoffman, J. Phys. Chem.
**86**, 1087 (1982). The current version is implemented only for close coupling calculations of a linear (vib) rotor hit by an atom; modifications for (a)symmetric top rotors hit by an atom should be straightforward. Some documentation written by J.M. Hutson (1985) is also available. - Identical linear molecule cross sections
- For identical linear rigid rotors it is sometimes convenient to convert identical molecule S-matrices (even and odd exchange symmetries on separate save tapes) to cross sections for distinguishable molecules. A self-contained FORTRAN program is available.

### ISIGU File Processor

The accumulated state-to-state cross sections (optionally) saved on the ISIGU file are useful for recovering from an abnormal program termination. A small FORTRAN program to read ISIGU and print cross sections is available.

Return to MOLSCAT Homepage