Part I. General Theory -- Landauer’s Principle and Thermodynamics -- On the Majorana Solution to the Thomas-Fermi Equation -- Spherically Averaged Densities as Basic DFT Variables -- Linear-Expansion Shooting Techniques Based on Minimization of Intra-Iteration Errors -- Part II. Atomic Systems -- Erfonium: A Hooke Atom with Soft Interaction Potential -- Spectroscopy of Radiative Decay Processes in Atomic Systems in a Black-body Radiation Field -- Relativistic Many-Body Perturbation Theory Approach to Computing Spectra of Complex Atomic Systems: Spectral Data for Ne-like Ions -- Relativistic Quantum Chemistry and Spectroscopy of Pionic Atomic Systems: Hyperfine Structure -- Part III. Molecular Systems -- Low-Cost Generation of Optimal Molecular Orbitals for Multi-Reference CI Expansion: Natural Orbitals versus Rényi Entropy-Minimized Orbitals Provided by the Density-Matrix Renormalization Group -- Formally Exact Many-Body Perturbation Theory with Optimized Zeroth Approximation in Calculations of Spectral Parameters of Diatomic Molecules -- Complexes of Counterion-Trapped Molecules: Extreme Polarity, Rich IR-Activity, and Internal-Field Moderated Transformations -- Designing an Iron-Based Bis(pyridyl)borate Complex Catalyst for Ammonia-Borane Dehydrogenation using Density Functional Theory -- Theoretical Investigation of Cl2, ClO and Cl2O Molecules -- Part IV. Biochemistry and Biophysics -- An Improved Fragmentation Modeling Aminoacids Under Ionizing Radiation. I. Threonine -- Computational Investigation of the Influence of the Acyl Group on the Reducing Abilities of Acylphloroglucinols -- Integrated in-Silico Drug Modeling for Viral Proteins.

This book contains peer-reviewed contributions based on talks presented at the 25th International Workshop on Quantum Systems in Chemistry, Physics, and Biology held in Toruń, Poland, in June 2022. The book reviews significant advances in concepts, methods, and applications of quantum systems in a broad variety of areas in modern chemistry, physics, and biology. In particular, it discusses atomic, molecular, and solid state structure, dynamics and spectroscopy, relativistic and correlation effects in quantum chemistry, topics of computational chemistry, physics, and biology, as well as applications of theoretical chemistry and physics in advanced molecular and nano-materials and biochemical systems. This book is aimed at advanced graduate students, academics, and researchers, both in university and corporation laboratories, interested in state of the art and novel trends in quantum chemistry, physics, and biology, and their applications. .