Sampling Rare Events in Hybrid Statistical Physics – Quantum Mechanical Studies of Hydrophobic Interactions in Liquids: A GPU Implementation Petre Lameski 1 , Ljupčo Pejov 2 , Leonid Djinevski 3 , Dimitar Trajanov 1 , Sonja Filip- oska 1 1 Ss. Cyril and Methodious University, Faculty of Computer Science and Engineering, Rugjer Boshkovikj 16, 1000 Skopje, Macedonia {petre.lameski,dimitar.trajanov, sonja.filiposka}@finki.ukim.mk 2 Ss. Cyril and Methodious University, Institute of Chemistry, Arhimedova 5, 1001 Skopje, Macedonia ljupcop@pmf.ukim.mk 2 FON University, Av. Kiro Gligorov 5, 1000 Skopje, Macedonia, leonid.djinevski@fon.edu.mk Abstract. A method for sampling rare events throughout hybrid statistical phys- ics quantum mechanical studies of hydrophobic interactions in liquid phases was analyzed and implemented on GPU architecture. The rare events considered in the present case are related to formation of the so-called dangling X-H bonds of small polar solvent molecules around notably non-polar solute molecules. The approach is based on detecting various populations of polar solvent molecules which reside in the first solvation shell around the non-polar solute and noting the differences between such populations. In particular, the search for structurally different populations of solvent molecules around the solute is started by detect- ing the differences in vibrational spectroscopic characteristics of the X-H stretch- ing frequencies, which could be computed by various approaches, such as, e.g. within the Stark shift approximation. The results show x25 overall speedup of the GPU implementation compared to the sequential implementation. Keywords: Rare Events, Hydrophobic Interactions, Statistical Physics Simula- tions, GPU, CUDA. 1 Introduction Hydrophobic intermolecular interactions have become increasingly popular in the last decade. The relevance of these noncovalent forces arises from the fact that they occur in realistic systems, which are particularly relevant to biomedical sciences. For exam- ICT Innovations 2015 Web Proceedings ISSN 1857-7288 154 S. Loshkovska, S. Koceski (Editors): ICT Innovations 2015, Web Proceedings, ISSN 1857-7288 © ICT ACT http://ictinnovations.org/2015, 2015