Applications
At present, no complete open source applications are publicly available. However, there are plans to make the applications listed below available if there is sufficient interest.
FCFRKR - Franck-Condon factors and RKR potentials
In the 1980s and 1990s in particular, I collaborated with my brother to develop several programs for spectrum simulation for diatomic molecules, most notably the program package FCFRKR.
The FCFRKR program package deals with the construction of RKR potentials and the solution of the Schrödinger equation for the nuclear motion of diatomic molecules (vibrational-rotational wave functions). The calculation of overlap integrals, Franck-Condon factors, dipole matrix elements, and Einstein A-factors can be selected in the program. In addition, options are available for calculating -centers and determining distortion constants ( and ).
The original Fortran source code is available in the Elsevier Data Repository. However, the code is likely to be relatively difficult to use, as it was largely developed for mainframe computers of the time.
In order to preserve the programs in a usable form for posterity, there are plans to adapt them for use on standard PCs and make them available.
Cash register software
For the ecumenical Lichtblick Café + mehr run by the Protestant Brückenschlaggemeinde Köln-Flittard / Stammheim church, I developed and maintained the cash register software for the café and shop areas based on standard PCs from 1996 to 2020. In 2021, the software was replaced by commercial solutions because the presbytery considered it too costly to adapt it to support a Technical Security Device (TSE) required by the German tax authorities.
It is indeed technically not feasible to adapt the cash register software for the café area, but the cash register software for the shop area could in principle be modernized accordingly.