Introduction

The CPL code of the Amsterdam Density Functional program system allows the user to calculate Nuclear Spin-spin Coupling Constants (NSSCCs) [1,2]. NSSCCs are usually observed in NMR (Nuclear Magnetic Resonance) spectroscopy and give rise to the splitting of the signals of the NMR spectrum in multiplets. They contain a wealth of information about the geometric and electronic structure of the compound being investigated.

The calculation needs a standard TAPE21 ADF output file. CPL reads also an input key and optional settings from stdin (usually from an input file). Technical parameters such as the maximum memory usage can be set here as well.

One of the key features of the program is its ability to treat heavy nuclei with the ZORA relativistic formalism. We refer the reader to the literature for details about our implementation [1,2]. Please use the information printed in the output header of the CPL program in order to provide references of this work in scientific publications.

Please note that the CPL program has been developed only very recently. CPL provides the main functionality in order to evaluate accurate NSSCCs based on DFT, as well as many additional features in order to provide an analysis of the results. Additional features that increase the range of applicability, result in faster program execution, or allow for a more extended analysis of the results will be implemented for future versions. Please report bugs or suggestions to SCM at support@scm.com.