opd program for the calculation of the scaled Osipov-Pickup-Dunmur chirality index

This is a very simple implementation of the scaled Osipov-Pickup-Dunmur chirality index calculation. This is a free software written in Fortran 2003 language, being available at https://github.com/colombarifm/opd_chirality_index under the GPLv3+ License. It was developed and tested under Linux environment with gfortran 7.5+ compilers.

Install

See installation instructions

Usage

It reads a simple .xyz coordinate file and returns both scaled (G0,s) and unscaled (G0) values

./opd --input <file.xyz>  > output.log

It can also run in parallel by setting the threads for OpenMP

export OMP_NUM_THREADS=<ncores>

As an example, the scaled Osipov chirality index (G0s, as reported on Solymosi et al. 2002) calculation was performed for multiple biphenyl conformations along its torsional profile (structures obtained at the GFN2-xTB level), as shown below:

Links for important articles

• Osipov (1995) M. A. Osipov, B. T. Pickup, D. A. Dunmur. A new twist to molecular chirality: intrinsic chirality indices. Mol. Phys., 84, 1193-1206 (1995)

• Solymosi (2002) M. Solymosi, R. J. Low, M. Grayson, M. P. Neal. A generalized scaling of a chiral index for molecules. J. Chem. Phys., 116, 9875-9881 (2002)

• Hattne (2011) J. Hattne, V. S. Lamzin. A moment invariant for evaluating the chirality of three-dimensional objects. L. R. Soc. Interface, 8, 144–151 (2011)

Directory organization

• src: The source code
• biphenyl_test: Input files for the calculation of the torsional profile of biphenyl