SCELib4.0: The new program version for computing molecular properties in the Single Center Approach

SCELib is a computer program which implements the Single Center Expansion (SCE) method to describe molecular electronic densities and the interaction potentials between a charged projectile (electron or positron) and a target molecular system. The first version (CPC Catalog identifier ADMG_v1_0) was submitted to the CPC Program Library in 2000, version 2.0 (ADMG_v2_0) was submitted in 2004 and version 3.0 (ADMG_v3_0) was submitted in 2009. We here announce the new release 4.0 which presents additional features with respect to the previous versions aiming at a significant enhancement of its capabilities to deal with larger molecular systems. In SCELib 4.0 we implemented an automatic R grid generator based on a screened nuclear potential. By coupling the R generator with a parametric θ, ϕ definition of the angular grid, one is then able to define the 3D grid which best follows the molecular shape of systems as large as nucleotides and DNA fragments. The list of supported architectures has been updated and the code already ported in v3.0 to hybrid platforms based on NVIDIA GPU, has now been fully ported in double precision arithmetic and parallelized with MPI under either Linux or Microsoft Windows operating systems. The resulting benchmarks of the new code will be discussed in details and for the first time we present the performance test on a system as large as the Cytidine Mono Phosphate (CMP) which at present is the largest system ever simulated with this and related kind of codes.