Program RKR1

RKR1 is R.J. Le Roy's program for applying the first-order Rydberg-Klein-Rees procedure to spectroscopic constants for a diatomic molecule to determine its potential energy function. This program allows the vibrational energies and inertial rotational constants to be defined by pure Dunham expansions, by pure near-dissociation expansions (NDEs), or by mixed Dunham/NDE functions. For a case in which only vibrational data are available, it allows an overall potential to be constructed by combining directly-calculated well widths with inner turning points generated from a Morse function. It also allows one to automatically smooth over irregular or unphysical behaviour of the steep inner wall of the potential.

The source code for Version 2.1 of program RKR1 and the associated user manual University of Waterloo Chemical Physics Research Report CP-657R2 (2016) are distributed free of charge. However, its use should be acknowledged by citation of the above report. This manual presents a brief summary of the computational methodology and a detailed description of the nature of the input data file and the options invoked by various input parameter choices. This version of the also contains a full derivation of the RKR equations in an Appendix. The FORTRAN source code and the sample data file used to generate the illustrative outputs shown in the manual are automatically distributed (by e-mail) to those who fill in the following form: Download RKR1v2.1 . The only non-cosmetic change from Version 2.0 of this code are that it uses the 2010 values of ħ and its atomic masses subroutine incorporates the 2012 version of the atomic mass table.

I would be pleased to receive information regarding apparent or real malfunctions of this code or weakness in the documentation. However, the program should be fairly robust, and is fairly extensively commented internally. If you encounter problems obtaining either the source code or a printed copy of the manual, please contact the author by e-mail. Queries regarding this program or its distribution should be addressed to R.J. Le Roy (519) 888-4051; leroy @

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