Hosted at the Hotel “Stary Tartak” in Iława, in the heart of Masurian Lakes, Poland, this training school is tailored for students and early-career researchers interested in the analysis of intermolecular interactions across a wide range of molecular systems in confined astrochemical environments. The school is also open to experienced researchers willing to learn about modern theoretical tools and/or analysis of weak interactions from the experimental point of view.

The multidisciplinary program aims to provide participants with a structured introduction to the fundamentals and advanced aspects of theoretical, computational, and experimental approaches that allow detailed analysis and understanding of weak inter- and intramolecular interactions. Covered topics will range from introductory to advanced, supplemented by hands-on tutorials, exercises, and computer simulations to encourage active learning and skill development.

The 2026 edition will focus on the evolution of spectral signatures of prebiotic molecules: from gas phase to confined astrochemical environments such as interstellar ices, grains, and planetary soils, by gradually increasing the size and complexity of studied molecular systems.

Highlights of the program:

• Fundamental aspects of weak interactions
• Analysis of weak interactions by means of symmetry-adapted perturbation theory (SAPT)
• Modeling of multi-dimensional potential energy surfaces (PES)
• Analysis of fingerprints of weak interactions in the experimental Infrared spectra
• Simulation of Infrared spectra by Vibrational Perturbation approaches (VPT2)

All topics considered will be complemented by short hands-on training sessions. Participants will gain practical experience with computational tools and experimental techniques, preparing them to address challenges in both academic and industrial settings.

The COST Action COSY aims to provide a computationally and experimentally sound foundation for the fundamental understanding and control of confined molecular systems. The resulting outcome will be translated into useful knowledge forming the basis for applications. These range from creating a new generation of materials including biomaterials, with immediate transfer to industry, to disclosing the chemistry occurring in space. To this end, COSY will combine new cutting-edge experimental techniques for the synthesis of novel nanomaterials and high-resolution characterization thereof, with state-of-the-art first principles modelling. The most advanced methods for molecular motion as well as modern artificial intelligence, machine learning technologies, and big data science will be applied.

COSY COST Action coordinators: María Pilar de Lara-Castells (Chair), Cristina Puzzarini (Vice Chair)